'pH-activated' is a compound formed from 'pH' and 'activated'. 'pH' originates from the term coined by Danish chemist Søren P. L. Sørensen (1909), ultimately from the Latin phrase 'potentia hydrogenii' where 'potentia' meant 'power' and 'hydrogenii' meant 'of hydrogen'. 'activated' originates from Latin, specifically the word 'activare', where 'activus' meant 'active'.

'pH' was introduced in 1909 by Sørensen and adopted into scientific English; 'activate' changed from Latin 'activare' to Old French 'activer' and eventually became the modern English verb 'activate', whose past participle is 'activated'. Together they formed the compound adjective 'pH-activated' in technical usage.

Initially, 'activate' meant 'to make active' in general use; over time, with scientific compounding like 'pH-activated', the phrase came to mean specifically 'made active in response to pH changes' in technical and biomedical contexts.