DELTA (DEscription Language for TAxonomy) is a data format used in taxonomy for recording descriptions of living things. It is designed for computer processing, allowing the generation of identification keys, diagnosis, etc.
It is widely accepted as a standard, one of only a few such standards. Quite a bit of software is available for various tasks, using this format. There is a website on DELTA, linking to many databases in this format.
It was devised by the CSIRO Australian Division of Entomology in 1971 to 2000, with a notable part taken by Dr. Michael J. Dallwitz.