moule

mould (UK), mold (US); matrix; (cake) tin (UK), pan (US)

Inherited from Old French modle, an old (11th century) borrowing from Latin modulus (“measure”) (compare Catalan motlle). Doublet of module, a more recent borrowing.

mussel; idiot, prat, twit; cunt

Inherited from Old French moule, from Vulgar Latin *mŭsclus, from Latin mūsculus. Doublet of muscle.