Altdesc

Altdesc is a shorthand term used in digital content management and accessibility contexts to refer to an alternate description text associated with non-text media, such as images, videos, or diagrams. It is not a formal standard in itself, but readers may encounter it in documentation or CMS interfaces as a field name or descriptor for descriptive metadata.

Purpose and scope: The intent of an altdesc is to provide a textual description that conveys the essential content and function of the media when the media cannot be perceived visually. This complements other descriptive fields, such as captions, and can be used by assistive technologies to communicate meaning to users who rely on screen readers.

Usage considerations: In practice, an altdesc should be concise yet informative, avoiding non-informative phrases and focusing on content and purpose. It is typically distinct from a caption, which may be longer and provide context or storytelling elements. In web accessibility, a related concept is alt text, which serves a similar purpose; the term altdesc may be used interchangeably in some systems, but its exact semantics depend on the platform.

Relation to standards: While WCAG guidance emphasizes providing meaningful alt text for images, there is no universal standard specifically named altdesc. Some content management systems implement an altdesc field as part of image metadata or accessibility settings, sometimes alongside a separate caption or description field.

See also: alt text, accessibility, WCAG, metadata, IPTC, image caption.