'acidoid' originates from the combination of 'acid' and the suffix '-oid', where 'acid' refers to a chemical substance with a pH less than 7, and '-oid' means 'resembling or like'.

'acidoid' was formed by combining the word 'acid' with the suffix '-oid', which is used to form adjectives and nouns indicating resemblance.

Initially, it meant 'resembling an acid', and this meaning has largely remained the same in modern usage.