2. (Steam Engine) A gudgeon on each side of an oscillating steam cylinder, to support it. It is usually
tubular, to convey steam.
Trunnion plate (Gun.),
a plate in the carriage of a gun, mortar, or howitzer, which covers the upper
part of the cheek, and forms a bearing under the trunnion. — Trunnion ring (Gun.), a ring on a cannon
next before the trunnions. [R.]