Gue'la is the term in the T'au Lexicon, the language of the T'au, for the Human species.
It contasts with the term Gue'vesa which means "Human Helper" and is the name given to those Humans who have willingly joined the multispecies T'au Empire and now serve the Greater Good, including sometimes as auxiliary military forces to the Fire Caste.
Sources
- Codex: Tau (3rd Edition), pg. 57