This guide is designed to give sellers a practical understanding of the topic before they make marketplace or business decisions. Requirements and platform policies can change, so current official marketplace information should always be checked for time-sensitive details.
SKU
Stock Keeping Unit: an internal identifier used to connect a sellable item or variant to inventory, cost and order records.
ASIN
Amazon Standard Identification Number: an identifier used within Amazon's catalog. Sellers should use catalog identifiers accurately and follow current marketplace requirements.
Item specifics
Structured eBay listing attributes that describe characteristics of an item and help buyers understand/filter listings.
Handling time
The time a seller allows between an order and handing the shipment to the carrier, subject to marketplace definitions and settings.
Selling limit
A marketplace-controlled constraint on how much a seller may list or sell. Current limits can change and should not be treated as permanent guarantees.
Seller level
An eBay performance classification based on current marketplace standards and seller performance information.
Account Health
Amazon's seller-facing area for important policy/performance information. Sellers should review the current dashboard because interfaces and measures can change.
Contribution margin
Selling price minus the variable costs attributable to the sale. Businesses define the exact internal calculation according to their accounting model.
Stockout
A situation where sellable inventory is unavailable for demand. Poor synchronization can also create a virtual stockout or overselling.
Safety stock
Extra inventory held to absorb uncertainty in demand or replenishment lead time.
Return rate
Returns divided by a relevant sales/order base for a defined period. Use a consistent definition when comparing products.
Root cause
The underlying process or condition that produced an issue, as distinct from the visible symptom.
Canonical URL
The URL a site indicates as the preferred version of a page among duplicates or near-duplicates. Canonicalization should be consistent with internal links and sitemaps.
Structured data
Machine-readable markup describing page content. It must accurately represent visible page content and follow the applicable search-engine guidelines.
Crawlable link
A normal HTML link that search engines can follow to discover another page. Important category, guide and product pages should be reachable through site navigation.
Related resources
Compare the eBay seller guide and Amazon seller guide.