'base-tolerant' originates from Modern English as a compound of 'base' and 'tolerant'. 'base' (in general English) comes via Old French 'base' and Late Latin 'basis' (from Greek 'basis'), while 'tolerant' comes from Latin 'tolerans', present participle of 'tolerare' meaning 'to bear' or 'to endure'.

'base' became used in scientific contexts (including chemistry) from Early Modern to Modern English to denote substances with alkaline properties; 'tolerant' developed from Latin into Middle and Modern English meaning 'able to bear'. The compound form 'base-tolerant' is a modern technical formation used in scientific and engineering descriptions (primarily 20th–21st century).

Initially, 'tolerant' simply meant 'able to bear or endure'; when combined with 'base' the phrase specialized to mean 'able to withstand basic/alkaline conditions' in technical contexts, while occasional figurative uses retain the general sense of 'tolerant of something base'.