​ROWLOCK (pronounced rullock or rollock), a device on the gunwale of a boat in or on which an oar rests, forming a fulcrum for the oar in rowing. The word is a corruption due to “ row ” of the earlier “ oar-lock, ” O.E. drlbc, a lock or enclosed place for an oar. The simplest form of rowlock is a notch, square or rounded, on the gunwale, in which the oar rests; other kinds are formed by two pins or pegs, “ thole pins ” (thole being ultimately the same word as Norw. toll, a young fir-tree), and by a swivel with two horns of metals, pivoted in the gunwale or on an outrigger (see OAR).