ammunition

Ammunition comes from Middle French amunition, which arose when la munition ("the war supplies") was misheard and rebracketed as l'amunition — the article fusing onto the noun. Munition itself traces back through Latin mūnitiōnem to mūniō and ultimately the Proto-Indo-European root *mey-.

The word entered English already carrying its accidental extra syllable, and that misdivided French form became the standard English word for military supplies, distinct from its parent munition.

It shares its Latin root mūnitiōnem with the English word munition, which kept closer to the original French and Latin form without the mistaken article attached.