Amazon Seller Glossary (A–Z)

Indicates the advertising cost relative to the sales generated. Calculated as: ad spend ÷ ad sales × 100. A lower ACoS means your PPC campaign is more efficient (you're spending less relative to the sales generated). Example: a 20% ACoS means for every $20 spent on ads, you generated $100 in sales from those ads.

A business model where the seller purchases products from other sources (retail stores, outlets, e-commerce sites) at discounted prices to resell them on Amazon at a higher price. The arbitrager leverages the price difference as profit. It's a common strategy for new sellers, but you need to carefully select products with high demand and sufficient margin. Compare with Wholesale and Private Label.

The unique identifier code assigned by Amazon to every product in its catalog. Composed of 10 alphanumeric characters, the ASIN allows Amazon to track and catalog products. For example, by searching for an ASIN, you can find the exact corresponding product page. Note: for books, the ASIN often matches the ISBN. See also FNSKU and EAN/UPC.

Amazon's subscription program offering customers fast shipping (usually 1-2 days) for free plus other benefits (like Prime Video). For sellers, Prime is relevant because products managed through FBA automatically become Prime-eligible, making them more attractive to millions of Prime members. Having the Prime badge can increase sales and improve your chances of winning the Buy Box.

In the Amazon context, APIs allow external software (like SellerMagnet or other tools) to communicate with the Amazon platform and exchange data. For example, the Amazon MWS/SP-API allows you to download orders, update prices or quantities automatically. In short, Amazon APIs are digital "bridges" that enable automation and integration between Amazon and third-party applications.

Amazon's brand registration program for trademark owners. By enrolling a registered trademark in Brand Registry, you gain access to advanced tools to protect your brand (e.g., report violations, remove unauthorized listings) and features like A+ Content, dedicated Amazon Store, and Amazon Vine. Essentially, it protects your brand from counterfeits and hijackers while enhancing your brand presence on Amazon.

The Buy Box is the box on the Amazon product page with the "Add to Cart/Buy Now" button. The seller who "wins" the Buy Box captures most of the sales, since customers buy from the specific seller in the Buy Box without examining other offers. Factors like competitive pricing, logistics (Prime/FBA), seller performance, and stock availability influence Buy Box assignment. A Repricer can help you win it consistently.

Indicates a product's ranking in Amazon's sales charts within a specific category. A BSR #1 means that product is the best-seller in its category. BSR is updated frequently based on recent sales: the lower the number, the higher the relative sales volume. Sellers monitor BSR to evaluate product performance and estimate market demand. Tools like SellerMagnet Sourcer can help track BSR trends.

A sales technique that involves offering the customer related or complementary products to what they're buying. On Amazon, cross-selling happens through sections like "Frequently Bought Together" or "Customers who bought this also bought…". For a seller, effective cross-selling means increasing the average cart value by offering relevant additional products. Optimizing your listings can help boost cross-sell opportunities.

In the Amazon context, indicates the percentage of product page visitors who actually make a purchase. For example, if 100 people visit your product page and 10 buy, the conversion rate is 10%. It's a key indicator of listing performance: a high conversion rate suggests that the title, images, price, and reviews are convincing customers. Optimizing page content and pricing can improve this metric—see Amazon SEO.

A sales model where the seller doesn't physically hold inventory, but transfers customer orders directly to the supplier/manufacturer, who ships the product to the end buyer. On Amazon, dropshipping is only allowed if it complies with policies (for example, the package must not contain invoices or references to the external supplier, and the seller remains responsible for customer service). This model reduces initial inventory investment but may result in less control over quality and shipping times. Compare with FBA and FBM.

Amazon's advertising platform that allows sellers and brands to purchase display and video ad space both on Amazon and on external websites/apps (through Amazon Advertising). Amazon DSP enables advanced retargeting and brand awareness campaigns, reaching a targeted audience using Amazon's data. It's a tool used primarily by sellers with larger advertising budgets or brands looking to increase visibility beyond standard PPC sponsorships like Sponsored Products.

EAN (European Article Number) and UPC (Universal Product Code) are unique barcodes used to identify products globally. Amazon generally requires an EAN/UPC code to create a new product listing (unless you have a GTIN exemption or use an existing ASIN). Essentially, the EAN/UPC is the product's "ID number": for example, a book will have an ISBN, while a toy will have an EAN/UPC. Make sure to purchase valid codes (often through GS1) to avoid catalog errors.

Amazon's logistics service where Amazon handles storage, packing, shipping to customers, and post-sale support. The seller sends their inventory to Amazon warehouses (fulfillment centers) and delegates order management to them. FBA products get the Prime badge and have better chances of winning the Buy Box thanks to fast, reliable shipping. However, there are FBA fees to consider (fulfillment and storage fees) and you must follow preparation and shipment guidelines. See also FNSKU and IPI.

A fulfillment method where the seller ships products directly to the customer (also called "Merchant Fulfilled"). With FBM, when an order comes in on Amazon, the seller handles packing, shipping, and customer service themselves. Advantages: full control over stock and shipments, no FBA fees; can be ideal for bulky or slow-moving products. Disadvantages: no Prime badge by default (unless participating in Seller Fulfilled Prime), less appeal to Prime customers, and full responsibility for delivery timing and quality.

The identifier code used by Amazon to track products in its FBA fulfillment centers. Each unit you send to Amazon must have an FNSKU label so Amazon knows which seller it belongs to. The FNSKU is linked to the ASIN but is seller-specific. In practice, if two sellers sell the same ASIN via FBA, they'll have different FNSKUs, ensuring that when a customer buys from your offer, Amazon ships a product from your stock.

Ratings that customers leave about the seller (not the product). It's a star rating and comment reflecting the purchase experience (e.g., shipping times, communication, description accuracy). A high average feedback (close to 5 stars) and a good number of feedback ratings help your reputation and are considered by Amazon in account performance and Buy Box eligibility. Not to be confused with product reviews: seller feedback is about the service offered by the seller, while reviews are about product quality.

A term for an "intruder" on your Amazon product listing. It happens when another seller adds themselves as an offer on your ASIN (perhaps your branded product) without authorization, often selling a counterfeit or parallel version at a lower price. Hijackers particularly target brand owners: beyond stealing the Buy Box and sales, they can damage the product's image (if they sell poor copies that generate negative reviews). To protect yourself from hijackers, it's advisable to enroll your trademark in Brand Registry, monitor your listings, and report violations to Amazon.

The inventory performance index for FBA sellers, calculated by Amazon on a scale of 0-1000. It reflects how efficiently you manage stock in Amazon warehouses. Various factors influence IPI, including: sales rate relative to stock (sell-through), out-of-stock or excess inventory, stock without active offers, etc. A high IPI (e.g., 500+) indicates you're managing FBA inventory well (few stock-outs, little stagnant inventory), while a low IPI can lead to storage space restrictions. Keeping IPI above the minimum threshold (set by Amazon periodically, e.g., 400) is important to avoid FBA limitations.

A 13-digit code used as a unique identifier for books. On Amazon, a book's ISBN often serves as the product code (ASIN) for that publication. If you sell books, you'll know the ISBN as it's used to search for and add titles to the catalog. For sellers, it's essentially the "publishing equivalent" of the EAN/UPC.

A key term used for searches on Amazon. When a customer types a word or phrase in the search bar (e.g., "Italian coffee maker 3 cups"), the system compares these keywords with those present in titles, bullet points, descriptions, and backend keywords of product listings. Optimizing your listings with the most relevant keywords means improving your Amazon SEO (visibility in internal search results). Additionally, keywords are the foundation of PPC advertising campaigns: by choosing the right keywords, you can reach the right audience in your Sponsored Products.

The Amazon page dedicated to a product, containing title, images, description, bullet points, technical details, and reviews. Creating an excellent listing is fundamental for selling: a clear title rich in keywords, professional photos, bullet points highlighting benefits, and an accurate description increase customer appeal and improve conversion rates. Listing quality also affects ranking in Amazon searches. Optimizing listings is part of Amazon SEO strategies. Use the free Title Checker to validate your listing title against 22 compliance rules.

This was the name of Amazon's API platform for sellers (now largely replaced by the new SP-API). Amazon MWS allowed software and developers to interact with your account data (orders, inventory, reports) programmatically. For example, an order management tool could connect via MWS to automatically download orders and update availability. Although today we more often speak of Selling Partner API, many services and documentation still reference MWS.

A specific, narrow market segment that a product focuses on. Finding a profitable niche is the secret of many successful sellers: it means identifying a particular need of a defined audience (example: "eco-friendly yoga accessories for travelers") and serving that market with a dedicated offering. On Amazon, working in niches can mean less competition and more targeted customers, but it's important to verify there's sufficient demand. Product research tools help discover niches by monitoring BSR trends, search volumes, and competition.

The percentage of defective orders for a seller, a key performance metric on Amazon. It includes three components: negative buyer feedback, A-to-Z claims, and chargebacks related to orders. Amazon requires sellers to maintain ODR below 1% to avoid penalties or account suspension. For example, out of 100 orders, fewer than 1 should have serious problems. To keep ODR low, you need to offer excellent service: accurate descriptions, timely shipping, proper packaging, and responsive customer support.

A time-limited promotion on Amazon where a product is offered at a significant discount for a limited period (usually a few hours). Lightning Deals appear in special showcases (e.g., Deal of the Day page) and can generate sales and visibility spikes. Sellers can propose Lightning Deals through Seller Central, but Amazon applies selection criteria (e.g., sales history, product rating) and often a participation fee. They're useful tools during events like Prime Day or Q4 Black Friday to boost sales.

An online advertising model where the seller pays only when a user clicks on their ad. On Amazon, PPC mainly refers to internal advertising campaigns (Sponsored Products, Sponsored Brands, Sponsored Display): you create ads that appear in search results or on product pages and set a bid per click. A well-optimized PPC campaign increases product visibility and sales, but needs monitoring to ensure the cost per click is sustainable relative to sales generated (see ACoS).

A business model where an Amazon seller creates and sells products under their own brand. Instead of reselling existing brands, in Private Label you identify a product (often through OEM suppliers), customize it with your own brand and packaging, and import it to sell as your own. Advantages: complete control over branding, less Buy Box competition (being the only seller of your brand), and potentially higher margins. However, it requires investment in product development, marketing, and quality, plus brand protection from imitations (where Brand Registry comes in handy).

Amazon's annual sales event, exclusive to Amazon Prime members. It consists of days (usually two) with thousands of special offers in July or summer, often compared in impact to Q4 Black Friday. For sellers, Prime Day represents a huge opportunity to increase sales thanks to the enormous traffic of Prime customers looking for deals. Many sellers prepare extra stock, dedicated advertising campaigns, and Lightning Deals well in advance.

Amazon's logistics initiative for European sellers: it allows you to store inventory in one country but make products Prime-eligible across all EU marketplaces, with Amazon internally reallocating stock closer to customers. In practice, you ship products to a central warehouse (e.g., Germany) and Amazon distributes at no extra cost to other hubs across Europe based on demand. Pan-EU FBA simplifies international selling (no need to manually manage warehouses for each nation), but involves managing VAT aspects in multiple countries since stock is moved across borders.

Refers to the fourth quarter of the year (October, November, December), a crucial period for e-commerce and Amazon sales. Q4 includes Black Friday, Cyber Monday, and the entire holiday shopping season. Many sellers record very high percentages of their annual revenue in these three months. Preparing for Q4 means ensuring sufficient stock, optimizing listings, increasing advertising budgets, and planning promotional offers, since consumer demand reaches its peak.

Ratings and written opinions that customers leave on a product page after purchase. Product reviews (with star ratings) enormously influence buying decisions on Amazon: a product with many positive reviews will have higher conversions and may rank better in searches. Sellers must follow policies in review strategies (no incentives for positive reviews) and can use tools like Amazon's Request a Review or automated services to legitimately solicit customer feedback. See also Amazon Vine.

The protection Amazon offers buyers to ensure a refund when they're not satisfied with a Marketplace order. If a customer opens an A-to-Z Claim, Amazon evaluates the situation (product not received, different from description, defective, etc.) and may refund the buyer from the seller's funds if they deem the complaint valid. For the seller, an A-Z claim negatively impacts Order Defect Rate. Avoiding A-Z claims means providing accurate information, shipping on time, and promptly resolving any issues reported by customers.

Software that automatically adjusts your product prices on Amazon based on certain rules or algorithms. The main goal of a repricer is to keep prices competitive (e.g., to win or maintain the Buy Box) without you having to manually intervene 24/7. There's Amazon's free repricer (Automate Pricing) with basic rules, and more advanced third-party solutions that update prices more frequently, allow minimum margin logic, multi-account management, and results analysis. A good repricer helps increase sales and protect profits, avoiding both prices too high that lose visibility and excessive drops that erode margins.

Return on investment, expressed as a percentage, calculated as: net profit ÷ investment cost × 100. In the Amazon context, ROI is often used to evaluate the profitability of a product or advertising campaign. For example, if you spend $10 on goods and costs for a product and earn $30 net profit, ROI is 300%. It's important for sellers to estimate ROI before launching a product (considering production costs, shipping, FBA fees, advertising, etc.) to ensure it's worth the investment.

Amazon's web platform through which Marketplace sellers manage their business. Through Amazon Seller Central you can add new products or offers, update prices and quantities, manage orders, set up advertising campaigns, monitor performance with reports and metrics, open support cases, and much more. It's essentially the seller's "headquarters" on Amazon. A feature-rich interface that can initially seem complex: tools like SellerMagnet integrate via API to simplify and enhance some of these activities (e.g., more readable profit dashboards, repricing automation, custom alerts).

On Amazon, refers to optimizing product pages to rank higher in internal search results. It works with principles similar to Google SEO but applied to the marketplace: you need to include relevant keywords in the title, bullets, and backend, use quality images, get good reviews, and maintain a good conversion rate. All these factors contribute to your product listing's relevance and performance in Amazon's A9/A10 search algorithm. Good Amazon SEO increases your products' organic visibility, reducing dependence on paid advertising.

A pay-per-click ad format on Amazon. Sponsored Products campaigns promote specific products and appear both in search results (at the top or middle of the list, with "Sponsored" label) and on product pages of other items. When a shopper clicks the ad, they're taken to your product page and you pay the click cost. These sponsorships are a key tool for giving your products visibility, especially during launches or in highly competitive categories, and work based on keywords or product/category targeting chosen in the campaign.

The process of obtaining authorization to sell in product categories or brands initially blocked on Amazon. Some categories (e.g., Jewelry, Grocery) or brands require sellers to provide documentation (supplier invoices, licenses, certifications) to demonstrate reliability and compliance before they can create offers. This process is called ungating. If you want to expand your catalog into a restricted category, you must submit an approval request through Seller Central, attaching the required documents. Once approved, your account is "ungated" and you can freely sell those products.

A platform reserved for Amazon suppliers (first-party sellers). Unlike Seller Central (for third-party marketplace sellers), Vendor Central is used by brands and distributors who sell their products directly to Amazon wholesale. Amazon becomes the final retailer, offering products as "Sold and shipped by Amazon." Vendors have a different relationship: they receive purchase orders from Amazon, manage wholesale pricing, and have access to specific marketing tools (like free Amazon Vine, extended Display campaigns, etc.). The transition to Vendor Central happens only by Amazon invitation.

An Amazon program (part of Brand Registry) that helps sellers get reviews on new products through a community of top reviewers. The Vine Program allows registered brands to offer a certain number of free units of a new product to "Vine Voices" (trusted reviewers selected by Amazon); in return, these users will try the product and publish an honest review. It's a legal and transparent way to break the "zero reviews" cycle when launching an item. Note: there's a cost to enroll an ASIN and a quantity limit, but a handful of initial quality reviews through Vine can boost product trust.

A model where the seller purchases large quantities of products from official manufacturers or wholesalers to resell on Amazon (often on existing product pages, competing with other sellers). Doing wholesale means having B2B relationships with suppliers and often getting very low unit prices thanks to volume. It's the typical model for professional resellers: instead of hunting retail deals (arbitrage) or developing their own brand (private label), they choose established brands and resell them as authorized resellers. Important in this model is finding products with sufficient ROI, avoiding brands with too many resellers (Buy Box competition risk), and maintaining adequate stock levels.