'instant-release' originates from modern English as a compound of 'instant' and 'release'. 'instant' ultimately comes from Latin 'instans' (present participle of 'instare'), where 'in-' meant 'on/against' (or serving as an intensifier) and 'stare' meant 'to stand' or 'to be present'. 'release' comes from Old French 'releser'/'relacier' (via Middle English), where the prefix 're-' meant 'again/back' and the root (from Latin and Old French sources) carried the sense 'to loosen/set free'.

'instant' passed from Latin 'instans' into Old French (as 'instant') and then into Middle and Modern English with meanings like 'immediate' or 'pressing'. 'release' evolved from Old French 'releser' / Latin roots (related to 'relaxare') into Middle English 'relesen' and later Modern English 'release'. The compound 'instant-release' appears in modern technical and medical usage (20th century onward) to describe formulations that release drug immediately.

Individually, 'instant' originally meant 'standing upon' or 'urgent/present' and came to mean 'immediate'; 'release' meant 'letting go' or 'loosening'. Combined as 'instant-release', the phrase initially described a quick act of release and later specialized in pharmaceuticals to mean a formulation that releases its active ingredient immediately.