A gunwale (pronounced “gunnel”) is the upper edge or rail that runs along the top of a boat's side. If you're sitting in a canoe or rowboat, the gunwale is the rim you might grip with your hands or rest your arms on.

The gunwale is the strong edge or rail along the side of a boat. Today's boats don't carry cannons, but they still have gunwales: the sturdy edge that helps keep water out, provides a place to attach oars or fishing rod holders, and gives the boat structural strength.

In small boats like canoes, the gunwales are especially important. They're where paddlers can grab on if the boat tips, and experienced canoeists know not to load gear so high that it rises above the gunwales, since that makes the boat tippy and unsafe. On larger boats, the gunwale might be wide enough to sit or stand on. When someone says they've loaded a boat “to the gunwales,” they mean it's packed completely full and riding low in the water with cargo.