Amazon Seller Glossary: 50+ Terms Every Seller Needs to Know

A

A9 Algorithm

Amazon proprietary search algorithm that determines organic product ranking in search results. It weights relevance signals (keywords in listing) and performance signals (CTR, CVR, sales velocity) to decide which products appear first.

ACoS (Advertising Cost of Sales)

The ratio of ad spend to ad-attributed revenue. Formula: Ad Spend / Ad Revenue x 100. A 25% ACoS means you spent $25 to generate $100 in ad revenue. Lower is generally better, but acceptable ACoS depends on your product margin.

ASIN (Amazon Standard Identification Number)

A 10-character alphanumeric identifier assigned to every product on Amazon. Each variation (size, color) typically gets its own ASIN. The parent ASIN represents the product family; child ASINs represent individual variants.

A+ Content

Enhanced product description content available to Brand Registry members. Replaces standard text description with rich media modules including comparison charts, lifestyle images, and feature callout sections. Proven to increase conversion rates by 5-10%.

B

BSR (Best Seller Rank)

A numeric rank assigned to every product in every Amazon category based on recent sales velocity. Lower number equals higher rank (BSR #1 is the best seller). BSR fluctuates continuously and is used to estimate a product daily sales volume.

Buy Box

The prominent Add to Cart section on Amazon product pages. When multiple sellers offer the same product, Amazon algorithmically selects one to win the Buy Box. Winning criteria include price, fulfillment method (FBA favored), shipping speed, and seller metrics.

C

CTR (Click-Through Rate)

The percentage of shoppers who click on your listing after seeing it in search results. CTR = Clicks / Impressions x 100. A higher CTR indicates an attractive main image, competitive price, and strong review count. Low CTR is usually a main image problem.

CVR (Conversion Rate)

The percentage of product page visitors who make a purchase. CVR = Orders / Sessions x 100. Amazon average CVR is approximately 10-15% for Prime-eligible listings. Low CVR typically indicates listing quality issues (images, price, reviews, description).

F

FBA (Fulfillment by Amazon)

Amazon fulfillment service where you send inventory to Amazon warehouses and Amazon handles picking, packing, shipping, and customer service. FBA enables Prime eligibility and removes operational burden at the cost of per-unit fulfillment and storage fees.

FBM (Fulfillment by Merchant)

Fulfillment model where the seller handles all storage, packing, and shipping directly. Avoids FBA fees but requires operational infrastructure. Suitable for heavy/oversized products or sellers with existing logistics capabilities.

G

GTIN (Global Trade Item Number)

Universal product identifier encompassing UPC, EAN, and ISBN codes. Amazon requires a valid GTIN (typically a UPC barcode) for most product listings unless you have a Brand Registry GTIN exemption.

H - I

Honeymoon Period

Informal term for the early period after a new ASIN goes live when Amazon algorithm gives it elevated visibility to test market response. Strong sales velocity during this window accelerates long-term organic ranking. Duration is typically 30-90 days.

IPI (Inventory Performance Index)

Amazon score (0-1000) that measures how effectively you manage FBA inventory. Scores below 400 may trigger storage limitations. Optimize by reducing excess inventory, avoiding stockouts, and removing unsellable units.

K - L

ACOS vs TACOS

TACoS (Total Advertising Cost of Sales) measures ad spend against total revenue (both organic and ad-attributed), not just ad revenue. TACoS = Ad Spend / Total Revenue x 100. TACoS gives a more complete picture of advertising efficiency and is the metric sophisticated sellers track most closely.

Long-Tail Keywords

Specific, multi-word search phrases with lower search volume but higher purchase intent. Example: yellow silicone spatula set heat resistant vs spatula. Long-tail keywords convert better and have less competition - essential for new listings.

M - N

Negative Keywords

Keywords added to PPC campaigns to prevent your ads from appearing in irrelevant searches. Critical for reducing wasted ad spend. Example: if you sell premium spatulas, add free and cheap as negative keywords to avoid unqualified clicks.

NIS (New Item Setup)

The process of creating a new product listing on Amazon. NIS requires product details, images, pricing, and fulfillment setup. Errors in NIS (wrong category, missing required attributes) can suppress listing visibility.

P - R

PPC (Pay-Per-Click)

Amazon paid advertising model where you bid to show ads and only pay when a shopper clicks. Includes Sponsored Products (most common), Sponsored Brands, and Sponsored Display. PPC is the primary driver of visibility for new product launches.

ROAS (Return on Ad Spend)

Ad revenue divided by ad spend. ROAS of 4x means $4 in revenue for every $1 spent. Inverse of ACoS. Use ROAS for cross-channel comparison; use ACoS for Amazon-specific optimization.

Referral Fee

Commission Amazon charges per sale, ranging from 8-15% depending on category. This is separate from FBA fees. Referral fee is deducted automatically from your payment on every completed order.

S - V

Sales Velocity

Units sold per day, per week, or per month. The single most important signal in Amazon algorithm. High sales velocity earns organic ranking; declining velocity causes ranking to fall. Velocity is why launch strategy is so critical.

SFP (Seller Fulfilled Prime)

Program allowing FBM sellers to display the Prime badge by meeting Amazon strict speed and service standards. Requires a proven track record of on-time delivery and is difficult to qualify for, but allows FBM sellers to compete for Prime shoppers.

Vine Program

Amazon review program for Brand Registry members that allows trusted reviewers to receive products for free in exchange for honest reviews. Helpful for accumulating early reviews during product launches. Limited to 30 reviews per enrolled ASIN.

Frequently Asked Questions