the.com/oarlock

means A U-shaped or swiveling fitting fixed to the side of a boat that holds the oar in place and gives it a fulcrum to push against.

from A straightforward compound of 'oar' and 'lock' — 'lock' here used in its old sense of a fastening device that holds something secure while still letting it move, much as a 'lock' can mean a mechanism that controls motion rather than only sealing it shut. Oarlocks (also called rowlocks, especially in British usage) emerged as rowing boats evolved from simple paddling to true leverage-based rowing, where the oar needed a fixed pivot point against the hull rather than relying on the rower's grip and arm strength alone.