'three-toed' originates from English, specifically the words 'three' + 'toe' with the adjectival suffix '-ed', where 'three' meant 'three' and 'toe' meant 'digit of the foot'.

'three' comes from Old English 'þrīe' (from Proto-Germanic '*þrīz') and 'toe' comes from Old English 'tā'; the suffix '-ed' has long been used in English to form adjectives, and together they produced the compound adjective 'three-toed' in modern English.

Initially it was a straightforward compound meaning 'having three toes'; this literal meaning has remained essentially unchanged.