TRUNNION

Etymology

Noun

trunnion (plural trunnions)

One of the short stubby bearings on either side of a cannon; a gudgeon.

A similar rotational bearing comprising a rotating arc or ring sliding in the groove of a stationary arc, used in machinery to allow a workpiece to be moved relative to a fixed tool.

A similar rotational bearing used in automotive suspensions.

Source: Wiktionary

Trun"nion, n. Etym: [OF. trognon the stock, stump, or truck of a tree, F. trognon a core, stalk, fr.tron a trunk, stem. Cf. Trunk.]

1. (Gun.)

Definition: 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.

2. (Steam Engine)

Definition: 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.]

Source: Webster’s Unabridged Dictionary 1913 Edition