'alkalise' originates from Arabic, specifically the word 'al-qalī', where 'al-' meant 'the' and 'qalī' meant 'ashes of saltwort'.

'al-qalī' transformed into the French word 'alcali', and eventually became the modern English word 'alkali', from which 'alkalise' is derived.

Initially, it meant 'to make something alkaline', and this meaning has largely remained the same in modern usage.