An oar is a long pole with a flat, wide blade at one end, used to row a boat through water. When you pull an oar through the water, the blade pushes against it, moving the boat forward. Rowboats typically have two oars, one for each hand, and you sit facing backward while rowing, which feels backwards at first but lets you use your stronger back and leg muscles.

Larger boats might have multiple rowers, each with their own oar. In crew racing, eight rowers work in perfect rhythm, their oars dipping in and out of the water together like a synchronized machine. Viking longships had dozens of oars along each side, powered by warriors who could row for hours across stormy seas.

The phrase “put your oar in” means to give your opinion when nobody asked for it, like interrupting a conversation to add your thoughts.