All hyperlinks direct to Amazon pages.
Additional abbreviations and concepts that are missing are welcomed, as well as clarifications and edits.

Account health: overview of your seller account’s adherence to the performance targets and policies required to sell on Amazon.
API: Application Program Interface.
APvU: Add Products via Upload.
Arbitrage: the act of buying a product from one store (online or physical) to sell in another market (Amazon) at a higher price.
ASIN: Amazon Standard Identification Number. 14-digit alphanumeric code that identifies products on Amazon.
A to Z Guarantee: a protection granted to buyers when they purchase items. It covers the timely delivery and the condition of the items. It can be abused.
A to Z Claims: one of the biggest fears of many Amazon sellers. This is one of the most serious topics, widely discussed in the forums and open to way too many interpretations. This is Amazon’s guide on how to manage A to Z Claims.
B2B: business to business.
Barcode: method of representing data visually by varying the widths and spacing of parallel lines. Barcodes link manufacturers with products. The barcode of a product is expected to always be in the same location. If two items have the same barcodes, they must be the same product. A single barcode can be used an unlimited number of times for a same product, but it can only be used for that product. Amazon verifies the validity of Universal Product Codes (UPC) through the Global Standards 1 (GS1) database. It is Amazon’s express recommendation that UPCs are obtained directly from GS1.
BOGO: buy one get one.
Bookmarked post: an entry that s tagged by a seller to check/review/follow later. Sellers can check the entries that they have bookmarked accessing the Summary tab of their profile in the Amazon Service Seller Forums (upper right corner, click on the avatar, username, summary).
Brand: from google “a type of product manufactured by a particular company under a particular name.”
Brand registry: a program that allows verified brand owners to protect their brand.
Buy box: when multiple sellers offer the same ASIN the buy box is the algorithm that determines which seller gets the sale. It is measured as a percentage determined by variables that range from price, availability, proximity to the buyer and account health, among others.
Category: the way Amazon groups similar products. Different categories have different restrictions. Products need to be linked to a category.
Child product: check variations.
Counterfeit: from google “made in exact imitation of something valuable or important with the intention to deceive or defraud”.
CTR: Click-through-rate, percentage of shoppers who see and ad and click on it.
Customer: tricky term that even Amazon has trouble defining. It is never clear who the customer is, Amazon or the buyer? Sellers invoice Amazon, so strictly speaking Amazon is the customer of the sellers. Buyers who purchase through Amazon are invoiced by Amazon and claim they got the items from Amazon, so (again strictly speaking) they are not the seller’s customers. Amazon however uses the term indistinctly and it is a common cause of confusion.
DS: Drop Ship.
DSV: Drop Ship Vendor.
FBA: Fulfilled by Amazon, products are shipped to Amazon warehouses for Amazon to distribute.
FBM: Fulfilled by Merchant, seller handles the shipping logistics.
FC: Fulfillment center.
Flagged post: an entry in the Seller Forums that is being reported. When a post is flagged a box opens, the seller must indicate why a post is being flagged.
FNSKU: Fulfillment Network Stock Keeping Unit, also known as an “Amazon Barcode”. It is different from the ASIN. The FNSKU is a code that links a product to a seller, useful to track products in the Fulfillment Centers.
FTL: Full Truck Load.
Gated category: division of restricted products inaccessible to sellers without Amazon’s approval.
GS1: Global Standards 1, non-profit that develops global standards for business including the barcode. Amazon uses GS1’s database to check UPCs.
GTIN: Global Trade Item Number, a globally unique 14 digits number to identify trade items. The most common GTINs in Amazon’s catalogue are:
a) UPC: Universal Product Code
b) ISBN: International Standard Book Number
c) EAN: European Article Number
d) JAN: Japanese Article Number
IP: Intellectual Property.
Listing: product that is available on to an Amazon product detail page. Is the product page for the item being sold.
LTL: Less than Truck Load.
MAP: Minimum advertised price, the lowest price a retailer can advertise a product. Minimum price at which a product can be offered.
Marketplace: ecommerce platform where the products are being sold.
MOQ: Minimum order quantity, lowest possible order a manufacturer/distributor requests for a given product.
MSRP: Manufacturer Suggested Retail Price.
MWS: Marketplace Web Services, an environment for sellers to add applications to their account. It is not available for individual seller accounts.
OA: Online Arbitrage, sourcing products from an online marketplace to sell in another.
ODR: order defect rate, percentage of orders with defects on a given 60 days period.
OP: Original post, first post at the top of the page. Original Poster, person who started the post.
Parent Product: check variation.
PDP: Product Detail Page.
PL: Private label, a product manufactured under the name of a given brand and not the manufacturer.
POA: Plan of Action.
PPC: Pay per Click, related to advertisement.
Price: the amount at which a product is sold.
Product review: are the reviews to the product, not the seller. If a product with good reviews is being sold by a bad seller the product can be affected (late shipment, damaged, etc). To prevent this, sellers can also be reviewed on Seller Feedback.
RA: Retail Arbitrage, sourcing products from a store to sell in a marketplace.
ROI: Return on Investment.
SC: Seller Central
Seller: company or individual that sells goods through Amazon. Sellers have access to the forums.
Seller Feedback: are reviews to the seller of the product, not the product itself.
SFP: Seller fulfilled Prime, by invitation only, seller handles shipping logistics ensuring Prime speed delivery across the country.
Seller Forums: online community (borderline social network) created by Amazon for sellers. Sellers can ask questions, share experience and in some cases insult and/or give bad advice to other sellers. Forum is restricted to sellers, though the moderators are Amazon’s employees who can edit posts and answer questions. All forum moderators indicate their name at the beginning of their post and their avatar is black with an “a”. Participants of the forums are expected to follow the posting guidelines.
SKU: Stock Keeping Unit. The concept of the SKU is external to Amazon, it is assigned by the seller and it is the code that the seller uses to keep track of the products.
SS: Seller Support (waste of time).
Seller University: Amazon’s collection of videos and documents explaining how to sell on Amazon. It is the official source of information sanctioned by Amazon. It is free, it offers videos, pdf and articles.
Suspension: seller loses the right to sell but can appeal. If the appeal is denied the seller can still submit a revised Plan of Action (POA). If the seller is banned Amazon is no longer reading the emails and appeals.
Trademark: from google “a symbol, word, or words legally registered or established by use as representing a company or product.”
Trademark infringement: unauthorized use of a trademark. Common and grave problem in Amazon.
Variation: some items have different attributes like color or size. Products that have these types of attributes can be grouped together in a single family establishing the follow relationship:
a) Parent product: product displayed in the search results. It indicates what the group of products are (for instance: shirt).
b) Child Products: the variations of the product that are related to the parent (size, quantity, color, etc)