'heterocercal' originates from Greek, specifically the words 'heteros' and 'kerkos', where 'hetero-' meant 'different' and 'kerkos' meant 'tail'.

'heterocercal' changed from New Latin word 'heterocercus' (formed from Greek roots) and eventually became the modern English word 'heterocercal'.

Initially, it meant 'different tail' (a literal compound of Greek elements), but over time it evolved into the current technical zoological meaning 'having an asymmetrical tail with the upper lobe longer than the lower'.