Adjective

(en adjective)

Having two sides

Involving both sides equally.

(of an agreement) Binding on both of the two parties involved.

Having bilateral symmetry.

(anthropology) Involving descent or ascent regardless of sex and side of the family.

Adjective

(en adjective)

Shaped like a triangle.

* {{quote-book, year=1963, author=(Margery Allingham)

, title=(The China Governess) , chapter=Foreword citation , passage=A very neat old woman, still in her good outdoor coat and best beehive hat, was sitting at a polished mahogany table on whose surface there were several scored scratches so deep that a triangular piece of the veneer had come cleanly away, […].}}

Of, or pertaining to, triangles.

Having a triangle as a base; as, a triangular prism, a triangular pyramid.

Having three elements or parties; trilateral, tripartite.