What term describes the software code provided by an advertiser that calls their ad server for displaying advertisements?

The term that describes the software code provided by an advertiser to call their ad server for displaying advertisements is "Tags."

Tags are small snippets of code that allow for the tracking and management of digital advertisements. When an ad is set to be displayed, the tag triggers communication with the ad server to fetch the ad content. This mechanism is essential for numerous forms of digital advertising because it enables the dynamic delivery of display ads based on various factors such as user behavior, demographics, and context.

Tracking Code refers specifically to code used to monitor user interactions or conversions and is often different from code used solely for ad display. An Ad Network is a service that connects advertisers with publishers, helping to facilitate the sale of advertising space, while an Ad Exchange is a platform that automates the buying and selling of online media advertising inventory. Both of these concepts relate to the broader ecosystem of digital advertising but do not specifically refer to the code that serves advertisements.