side arm

a weapon, as a pistol or sword, carried at the side or in the belt.

Origin of side arm

First recorded in 1680–90

The cubic contents of the pressure tube and side-arm become increased, owing to the cup-like shape the paint film takes on.

Paint Technology and Tests |Henry A. Gardner
He didn't go to his cabin; didn't even take off his side-arm.

Subspace Survivors |E. E. Smith
Others to the Old-German, Laz, from latus; the weapon being therefore a "side-arm."

Ancient Armour and Weapons in Europe |John Hewitt
He had already unbuttoned his tailed tunic, and slung his belt and sabre or side-arm from his shoulders.

Jones of the 64th |F. S. (Frederick Sadleir) Brereton

Dirk, dėrk, n. a Highland dagger or poniard: a side-arm worn by midshipmen and cadets of the royal navy.

Chambers's Twentieth Century Dictionary (part 1 of 4: A-D) |Various