equivocation
Equivocation (noun) means (logic) A mistake in reasoning that comes from using one word with two different meanings.
Etymology
Attested from around 1380, from Middle English equivocacion, from Old French equivocation, from Medieval Latin aequivocātiō, from aequivocō, from Late Latin aequivocus (“ambiguous, equivocal”), from Latin aequus (“equal”) + vocō (“call”). It is a calque of Ancient Greek ὁμωνυμία (homōnumía).