'acid-tolerant' originates from the combination of 'acid,' from Latin 'acidus,' meaning 'sour,' and 'tolerant,' from Latin 'tolerare,' meaning 'to endure.'

'acidus' transformed into the Old French word 'acide,' and eventually became the modern English word 'acid.' 'Tolerare' transformed into the Old French word 'tolérer,' and eventually became the modern English word 'tolerant.'

Initially, 'acid' meant 'sour,' and 'tolerant' meant 'to endure.' Over time, 'acid-tolerant' evolved to mean the ability to withstand acidic conditions.