'epidote-free' is a modern English compound formed from 'epidote' and 'free'. 'epidote' originates from French 'épidote', ultimately from Modern Latin 'epidotus', and from Ancient Greek 'ἐπίδοτος (epidôtos)', where the element 'epi-' meant 'upon/added' and 'dôtos' related to 'given'. 'free' originates from Old English 'frēo' meaning 'not in bondage; exempt'.

'epidote' entered English via French 'épidote' and scientific Latin 'epidotus' in the late 18th to early 19th century as the mineral name; 'free' evolved from Old English 'frēo' through Middle English into modern English. The compound 'epidote-free' is a recent formation in scientific English, created by combining the established mineral name with the adjective 'free'.

Initially 'epidote' referred specifically to the mineral (name given based on Greek), and 'free' originally meant 'not enslaved' or 'exempt'; over time 'free' extended to mean 'without' in compounds (e.g. 'sulfur-free'), so 'epidote-free' now means 'without epidote'.