'anguillule' originates from French, specifically the word 'anguillule,' a diminutive of 'anguille' ('eel'); the suffix '-ule' (from Latin '-ulus/-ula/-ulum') meant 'little, small,' and the base traces to Latin 'anguilla' ('eel') from 'anguis' ('snake').

'anguillule' was borrowed from French scientific usage (18th–19th c.); the French 'anguillule' (diminutive of 'anguille') passed into English and eventually became the modern English word 'anguillule'.

Initially, it meant 'a very small eel,' but in scientific contexts it narrowed to the current sense of 'a minute eel-like nematode, especially the vinegar eel.'