'deaminate' originates from combining the Latin prefix 'de-' and the chemical term 'amine' (from French 'amine', ultimately from 'ammonia'), where 'de-' meant 'remove' and 'amine' referred to the class of compounds derived from ammonia.

'deaminate' changed from 19th-century chemical coinages that paired the prefix 'de-' with 'amine' (the term 'amine' itself emerging in early 1800s chemistry) and eventually became the modern English scientific verb 'deaminate'.

Initially, it meant 'to remove an amine group (or to convert an amine into a non-amine form)'; over time this has remained essentially the same and is now specifically used for 'removing an amino group' in biochemical contexts.