'allele' originates from the German word 'Allel,' which is a short form of 'allelomorph,' where 'allelo-' meant 'each other' and '-morph' meant 'form.'

'allelomorph' transformed into the modern English word 'allele' through scientific usage in genetics.

Initially, it referred to 'alternative forms of a gene,' and this meaning has largely remained the same in modern usage.