Rowlock /(rō"lŏk colloq. rŭl"ŭk)/

Row·lock

Rowlock

n.
  1. A contrivance or arrangement serving as a fulcrum for an oar in rowing. It consists sometimes of a notch in the gunwale of a boat, sometimes of a pair of pins between which the oar rests on the edge of the gunwale, sometimes of a single pin passing through the oar, or of a metal fork or stirrup pivoted in the gunwale and suporting the oar; same as oarlock. (Naut.) [Chiefly Brit.]
  2. One of the rings of masonry included in an arch having more than one ring.