Glossaryprogrammatic advertisingad inventory

Ad Unit

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Also known as: ad placement

A single unit of ad space available on a publisher's website or mobile app. Ad units represent the discrete slots into which advertisers serve creative — a banner position at the top of a webpage, an interstitial in a mobile game, or a video pre-roll on a streaming page are all examples of individual ad units.

Publishers organize their available inventory as a collection of ad units, each defined by attributes such as size, format, and placement on the page or screen. In programmatic advertising, these units are what get auctioned through supply-side platforms (SSPs) and ad exchanges when a user loads a page or opens an app.

Inventory
Also known as: ad inventory, ad space Ad inventory refers to all available ad space on a given site. The terms "inventory" and "ad space" are often used interchangeably in the industry. Inventory is typically divided…
Ad Network
An ad network is a technology platform that acts as a broker between a group of publishers and a group of advertisers, connecting supply and demand across the digital advertising ecosystem. Traditionally, ad networks…
Header Bidding (HB)
A technique used by publishers to collect multiple bids from demand sources — including DSPs and ad networks accessed via SSPs and ad exchanges — simultaneously, rather than sequentially. Publishers implement header…
Premium Inventory
Premium inventory refers to a publisher's most desirable ad placements — typically homepage positions and high-traffic pages that attract the greatest audience volume and attention. From the advertiser's perspective,…