trunnion

A pin or gudgeon, especially either of two small cylindrical projections on a cannon forming an axis on which it pivots.

One of the cylindrical projections on the sides of a cannon, cast or forged in one piece with the cannon itself, which support it on its carriage.

In steam-engines, a hollow gudgeon on each side of an oscillating cylinder, which supports the cylinder, and through which steam is received and exhausted.

A cylindrical projection on each side of a piece, whether gun, mortar, or howitzer, serving to support it on the cheeks of the carriage. See Illust. of cannon.

A gudgeon on each side of an oscillating steam cylinder, to support it. It is usually tubular, to convey steam.