The term 'BEAVER's Construction' refers to the building of dams by beavers. A DAM is a barrier constructed across a waterway to control the flow of water. The three-letter solution for this term is 'DAM'. Beavers are well-known for their ability to build dams, which are made from sticks, mud, and stones. These dams can be used to create ponds, which provide a safe habitat for the beavers and other animals.