Gunwale
The gunwale, pronounced "gunnel", is the top edge of the side of a boat. Originally the "Gun Wall" on a sailing ship of war. This would be the wall behind which the cannons were mounted. In modern boats, cannons are no longer standard equipment, but the designation remains.
On a canoe, the gunwale is typically the widened edge at the top of the side of the boat, where the edge is reinforced with wood, plastic or aluminum.
