The word "threesided" can be replaced with a number of synonyms such as triangular, tripartite, trilateral, three-cornered or three-edged. These words are used to describe objects or shapes that have three sides or angles. Triangular is the most commonly used synonym for threesided and is used to describe an object with three sides and three angles. Tripartite is used to refer to a divided object, place or organization that has three parts. Trilateral is a synonym that is commonly used to describe a shape or an object with three straight sides. Three-cornered and three-edged are also used to describe triangular objects or shapes, but are not as commonly used as the previous synonyms.