Definition of "trunnion"

trunnion

/ˈtɹʌn.jən/

noun
plural trunnions
1. One of the short stubby bearings on either side of a cannon; a gudgeon.
2. 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.
3. A shaft, held by a bearing, at each end or side of a rotatable object.
  Quotations
  To discharge, the conveyor is rotated laterally on its trunnions and the metal flows into a ladle carried on a travelling crane, which conveys it to the converter.
  1964 December, “Beyond the Channel: Belgium: Conveyance of molten iron”, in Modern Railways, page 432
4. A similar rotational bearing used in automotive suspensions.