Semuncia

thumb|upright|Roman , The '''''' was an ancient Roman bronze coin valued at one twenty-fourth of an , or half an , produced during the Roman Republican era. It was made during the beginning of Roman cast bronze coinage as the lowest valued denomination.

The most common obverse types were a head of Mercury or an acorn, and the most common reverse types were a prow or a . It was issued until about 210 BC, at about the same time as the was introduced.