Here's a growing list of common terms and acronyms used in the online retail industry:

1P
1st party sales. These are sales attributable to the channel, not to a marketplace seller. Amazon's 1P sales in 2015 represented roughly 40% of their total sales (GMV, see below). When you buy a product that says "ships from and sold by Amazon.com" on the Amazon webpage (ASIN, see below), that's a 1P transaction. When you sell product to Amazon

3P
3rd party sales. These are sales attributable to marketplace sellers. When you buy a product on Amazon that "ships from and sold by {seller name}",  or is "sold by {seller name} and Fulfilled By Amazon", that's a 3P transaction.

ACoS
Advertising Cost of Sale, this term is used by Amazon for their Sponsored Products advertising program. ACoS is calculated by dividing your ad spend by your revenue attributable to that ad spend. For example, if you spend $100 and generate $1,000 in revenue, your ACoS is 10%.

ASIN
Amazon Standard Identification Number. This is a 10-character alphanumeric value that uniquely identifies a product listing on Amazon. Example: B000GAWSDG

Backorder
When a sale occurs but there is no inventory available to fulfill (ship) the order to the customer. This is also referred to as overselling.

BC
BigCommerce.

Duplicate ASIN
Sometimes the same exact product has more than one ASIN because one or more seller created an alternate ASIN either intentionally or accidentally by providing slightly different information about the product -- typically an incorrect UPC.

eBay Category ID
The location in eBay's taxonomy where a product is categorized. For example, 31387 is the eBay Category ID for the following taxonomy: eBay (homepage) > Jewelry & Watches > Watches, Parts & Accessories > Watches

EAN
International or European Article Number. This is a 13-digit barcode number which is a superset of the 12-digit UPC. Learn more at Wikipedia.

FBA
Fulfilled by Amazon

GMV
Gross Merchandise Value. This is top line revenue for a channel, seller, geographic region or the entire industry. Example: Amazon's GMV was $225 billion in 2015. This means $225 billion worth of products were purchased across their online properties.

GS
Google Shopping.

GTIN
Global Trade Item Number. This is a family of product identification numbers developed by GS1 which includes UPC and EAN.  Learn more at Wikipedia.

Jet Browse Node ID
The location in Jet's taxonomy where a product is categorized. For example, 16000036 is the Jet Browse Node ID for the following taxonomy: Home > Jewelry & Watches > Men's Jewelry & Watches > Wrist Watches

Jet Fulfillment Node
A unique identification value provided by Jet for each warehouse a seller creates in their Jet Partner Portal. In order to provide inventory to Jet attributable to a specific warehouse, you need to create a Jet Fulfillment Node and pass this value to Jet each time an update is provided.

MOQ
Minimum Order Quantity. This is the minimum number of units a customer must purchase. Note, Zentail does not currently support this.

Multichannel
Also spelled multi-channel, this is concept of selling products on multiple sales channels. This most commonly refers to multiple online sales channels, most notably Amazon, eBay, Walmart, Jet.

Partner Portal
This is Jet's web interface for sellers on Jet.com. This is where a seller, or a vendor, can manage shipping settings, fulfillment information, and more.

Repricing
Also referred to as dynamic repricing, this is the use of software to adjust the price of your products on a given listing (typically on Amazon) based on the pricing offered by other sellers for that same exact product.

RMA
An RMA is a Return Merchandise Authorization - You would generate an RMA if you require the customer to send back an item in order to receive a refund.

Shopping Cart
This refers to the platform used to create a customized ecommerce website. Shopping carts typically have a robust ecosystem of template (theme) designers and 3rd party apps (commonly referred to as "extensions" and "plugins") that provide additional functionality. Examples include Shopify, BigCommerce and Magento.

SV
SkuVault.

UPC
Universal product code. This is a 12 digit number that is encoded on the barcode of a product. In an effort to ensure products are assigned by sellers to the correct listing, most marketplaces require a UPC code to be provided.