(astronomy) An autumn constellation of the northern sky whose brightest three stars form a small triangle. The constellation lies near Perseus, between Aries and Andromeda.

(astronomy) A relatively nearby spiral galaxy in the Local Group, together with the Milky Way galaxy. It is at a distance of approximately 2.6 million light years from Earth, in the direction of the constellation Triangulum.

(astronomy) A winter constellation of the southern sky, which has three bright stars that form a triangle. It lies north of the constellation Apus, between Ara and Circinus.