Amazon seller glossary.

The terms that come up most when you run a brand on Amazon, in plain English.

Advertising

ACoS (advertising cost of sale): Ad spend divided by the sales your ads were credited with, shown as a percentage. $1,000 of spend that drives $4,000 of attributed sales is a 25% ACoS. It measures how efficient the ads are.
TACoS (total advertising cost of sale): Ad spend divided by total sales, paid and organic. It shows how dependent the business is on advertising. A falling TACoS with rising sales usually means ads are building organic rank.
Break-even ACoS: The ACoS at which an ad-driven sale earns exactly zero profit. It equals your margin before advertising divided by the selling price. Above it, every ad-driven sale loses money. Calculate yours
ROAS (return on ad spend): Ad-attributed sales divided by ad spend. It's the inverse of ACoS: a 25% ACoS is a ROAS of 4.
Sponsored Products: Amazon's cost-per-click ads for individual products, shown in search results and on product pages. Usually the largest share of a brand's ad spend.
Sponsored Brands: Ads that feature a brand's logo, a headline and several products, or a video, typically shown at the top of search results.
Sponsored Display: Ads that reach shoppers based on the products they view or their interests, on and off Amazon. Often used for retargeting and defending product pages.

Landed cost: The full cost of getting one unit into Amazon's warehouse: manufacturing, packaging, freight, duties and prep.
Referral fee: Amazon's commission on each sale, charged as a percentage of the sale price. The rate depends on the product category.
FBA fulfillment fee: The per-unit fee Amazon charges to pick, pack and ship orders it fulfills. It depends on the product's size tier, shipping weight and price band, and Amazon revises the rates periodically.
Size tier: Amazon's classification of a product by its packaged dimensions and weight. It's a main driver of the FBA fee, so a measurement error that pushes a product into a larger tier overcharges every unit. How to check
FBA reimbursement: Money or replacement units Amazon owes a seller for eligible inventory that was lost or damaged in its network. Reimbursements are generally valued at your manufacturing cost, and claims have short time windows.
Stranded inventory: Stock sitting in an Amazon fulfillment center without an active, buyable listing. It can't sell but still incurs storage fees.

Best Sellers Rank (BSR): Amazon's ranking of a product's recent sales against others in the same category. The #1 product in a category or subcategory carries the Best Seller badge.
A+ Content: Enhanced images, comparison charts and text modules on a product page, available to brand-registered sellers. Used to answer the questions that stop shoppers from buying.
Brand Store: A free, multi-page storefront on Amazon for brand-registered sellers, with its own URL.
Amazon Vine: An Amazon program where brand owners provide free units to trusted reviewers, called Vine Voices, so new listings can earn early reviews. Eligibility rules and enrollment fees apply. Commonly used during launches.
Suppressed listing: A listing hidden from search and browse because required information is missing or doesn't meet Amazon's rules.
Account Health: The Seller Central dashboard that tracks policy compliance and performance metrics. Problems here can put selling privileges at risk.
Voice of the Customer: A Seller Central dashboard that shows customer complaints and return reasons by listing, used to spot product, listing or packaging problems.
Search Query Performance: A Brand Analytics report showing the searches that led shoppers to your products, with your share of impressions, clicks, add-to-carts and purchases.

Seller Central (third-party, or 3P): The account a brand or merchant uses to sell its own products on Amazon. The seller sets the price, manages listings and receives funds 7 days after each order is delivered. Selling direct vs. Vendor Central
Vendor Central (first-party, or 1P): An invitation-only program where Amazon buys products at wholesale and resells them itself. Amazon sets the retail price and controls the listing, and vendors are typically paid on longer terms.
Amazon Brand Registry: Amazon's program for brand owners with a registered or pending trademark. It gives the brand's content priority on product pages, tools to report counterfeits and infringement, and access to Brand Analytics, A+ Content and Brand Stores.
MAP (minimum advertised price): The lowest price a brand allows authorized sellers to advertise its products at. Amazon doesn't enforce MAP, so brands manage it through their own reseller agreements.
Buy Box (Featured Offer): The "Add to Cart" and "Buy Now" section of a product page, which Amazon officially calls the Featured Offer. When several sellers offer the same product, Amazon chooses which offer wins it, and most sales go through the Buy Box.