Rowlock

n. [ For oarlock; AS. ārloc, where the second part is akin to G. loch a hole, E. lock a fastening. See Oar, and Lock. ] 1. (Naut.) 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. [ Chiefly Brit. ] [ 1913 Webster +PJC ]

2. One of the rings of masonry included in an arch having more than one ring. [ PJC ]