'pH-sensitive' originates from English, specifically the compound of 'pH' and 'sensitive,' where 'pH' combines 'p-' (from German 'Potenz', 'power') and 'H' ('hydrogen')—a notation coined by S. P. L. Sørensen in 1909—and 'sensitive' ultimately comes from Latin 'sentīre' meaning 'to feel' via French 'sensitif'.

'sensitif' transformed into Middle English/early Modern English 'sensitive', and with the 1909 scientific notation 'pH', eventually became the modern English compound 'pH-sensitive'.

Initially, 'sensitive' meant 'responsive to stimuli or easily affected'; combined with 'pH', the meaning specialized to 'responsive to acidity/alkalinity', which is the modern technical sense.