'underbite' originates from English, specifically the components 'under' and 'bite', where 'under' meant 'below' and 'bite' meant 'to cut or wound with the teeth.'

'under' comes from Old English 'under' and 'bite' comes from Old English 'bītan'; the compound 'underbite' developed in Modern English as a descriptive term for a dental alignment in which the lower teeth extend beyond the upper teeth.

Initially the elements separately meant 'below' and 'to bite'; over time the compound came to be used specifically for the dental condition 'lower teeth/jaw project beyond the upper teeth.'