'alkali-tolerant' is a compound formed from 'alkali' and 'tolerant'. 'alkali' originates from Arabic, specifically the word 'al-qaliy' (often written 'al-qaly' or 'al-qaliy'), where 'al-' meant 'the' and 'qaliy' meant 'ashes (of saltwort) used to produce alkaline substances'. 'tolerant' originates from Latin, specifically the present participle 'tolerans' (from the verb 'tolerare'), where 'tolerare' meant 'to endure'.

'alkali' entered scientific English via Medieval Latin/Spanish in the 16th–17th centuries from Arabic 'al-qaliy'; 'tolerant' came into English via Old French from Latin 'tolerans'. The compound adjective 'alkali-tolerant' is a modern formation used in scientific and agricultural contexts from the 19th–20th centuries onward.

Individually, 'alkali' originally referred to ashes used to make alkaline substances and 'tolerant' meant 'able to endure'; over time, their compound developed the technical meaning 'able to endure alkaline (high-pH) environments' used in biology, agriculture, and materials science.