When you first start learning about Amazon FBA you'll quickly run into a wall of acronyms and jargon — BSR, ROI, OA, ASIN, Buy Box. It can feel overwhelming before you've even started. This glossary covers every term you're likely to come across as a beginner, explained in plain English with no fluff.

Bookmark this page — you'll find yourself coming back to it. If you're completely new, our Start Here guide is the best place to begin.

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A

ASIN
Amazon Standard Identification Number
A unique 10-character code Amazon assigns to every product listed on its marketplace. Think of it as the product's ID number. When you're researching a product, the ASIN is what you'll use to look it up directly on Amazon.

B

BSR
Best Seller Rank
A number Amazon assigns to every product showing how well it's selling compared to other products in the same category. The lower the number, the better it's selling. A BSR of 1 means it's the best-selling product in its category. A BSR of 161 — like the Stanley bottle deal featured in our online arbitrage guide — means it's in the top 1% of its category, which signals very strong, consistent sales.
Buy Box
The Default "Add to Basket" Button
The Buy Box is the white box on the right side of an Amazon product page that contains the "Add to Basket" button. When multiple sellers offer the same product, only one wins the Buy Box at a time — and that seller gets the sale. Winning the Buy Box consistently is key to making sales as an FBA seller.

C

COGS
Cost of Goods Sold
The total amount you paid for the products you've sold. If you bought 40 Stanley bottles at £22 each, your COGS is £880. Understanding your COGS is essential for calculating your actual profit accurately.

F

FBA
Fulfilment by Amazon
Amazon's service where you send your stock to their warehouse and they handle all storage, packing, and delivery on your behalf. Every time a customer orders your product, Amazon fulfils the order automatically. See our full guide: What is Amazon FBA and how does it work?
FBM
Fulfilment by Merchant
The alternative to FBA — where you store and ship orders yourself rather than using Amazon's warehouse. Most beginners choose FBA because it's simpler and qualifies products for Prime delivery, but FBM is an option for certain products or situations.

G

Gating
Category or Brand Restrictions
Some categories and brands on Amazon require approval before you can sell them. This is called being "gated." You'll need to apply and sometimes provide invoices or other documentation to get ungated. Common gated categories include health and beauty and certain electronics brands.

I

IP Complaint
Intellectual Property Complaint
A complaint filed by a brand owner claiming you're infringing on their intellectual property — for example, selling counterfeit goods or using their branding without permission. IP complaints can result in your listing being removed or your account being suspended, so it's important to only source genuine products from legitimate retailers.

K

Keepa
Price & Sales History Tracking Tool
Keepa is a tool that tracks the price history and BSR history of Amazon products over time. It's one of the most important tools for online arbitrage sellers — it shows you whether a product sells consistently or only spikes occasionally, and whether the price is stable or volatile. Most experienced sellers won't buy a product without checking Keepa first.

L

Listing
A Product Page on Amazon
A listing is the product page on Amazon where customers find and buy a product. With online arbitrage, you're typically selling on an existing listing rather than creating a new one. The quality of the listing — title, images, description — affects how well the product converts visitors into buyers.

M

MOQ
Minimum Order Quantity
The minimum number of units a supplier will sell you in a single order. Less relevant for online arbitrage — where you're buying from retailers — but worth knowing as you learn more about the FBA model.

O

OA
Online Arbitrage
Buying products from online retailers at a lower price and reselling them on Amazon for a profit. One of the most beginner-friendly ways to get started with Amazon FBA. Read our full guide: What is online arbitrage and how does it work?

P

Prime
Amazon Prime
Amazon's subscription service that gives customers free next-day delivery on eligible products. FBA products automatically qualify for Prime, which makes them significantly more attractive to buyers. This is one of the biggest advantages of using FBA over fulfilling orders yourself.
Prep Centre
Third-Party Preparation Facility
A third-party warehouse that receives your stock, labels it, inspects it, and ships it to Amazon's fulfilment centre on your behalf. Useful if you don't want to handle products at home or if you're scaling up to larger volumes.

R

ROI
Return on Investment
A percentage that shows how much profit you made relative to what you spent. If you spent £880 on stock and made £366.80 profit, your ROI is 41.68% — exactly like the Stanley bottle deal in our online arbitrage guide. Most experienced sellers aim for a minimum ROI of 30% per deal.
Replenishable
A Product You Can Buy Again and Again
A replenishable product is one you can source repeatedly from the same or similar retailers. These are gold for online arbitrage sellers because once you find a profitable deal you don't have to keep searching — you just reorder. Evergreen, consistently selling products make the best replenishables.

S

Seller Central
Amazon's Seller Dashboard
The online platform where you manage your Amazon seller account. Everything lives here — your listings, inventory, orders, payments, and performance metrics. It's where you'll spend most of your time as a seller.
Sourcing
Finding Products to Sell
The process of finding profitable products to buy and resell on Amazon. For online arbitrage sellers, this means browsing retailers and comparing prices to what's selling on Amazon. Sourcing is the skill that separates profitable sellers from unprofitable ones — the better you get at it, the more you earn.

V

VAT
Value Added Tax
A UK tax applied to most goods and services. You don't need to be VAT registered to start selling on Amazon — registration is only required once your taxable turnover exceeds £90,000. As your business grows it's worth speaking to an accountant about the implications of VAT registration for your margins.

Real Proof These Terms Matter

Understanding terms like BSR, ROI, and replenishables isn't just theory — it's what separates sellers who make money from those who don't. The founder of The FBA Blueprint used this exact knowledge to generate over £2,000,000 in Amazon FBA sales starting from nothing. The fundamentals matter.