noun, genitive Tri·an·gu·li [trahy-ang-gyuh-lahy] /traɪˈæŋ gyəˌlaɪ/. Astronomy.
Origin of Triangulum
Examples from the Web for triangulum
The Andromeda Nebula is apparently less advanced toward transformation into stellar bodies than is that in Triangulum.Curiosities of the Sky|Garrett Serviss
Triangulum and Aries are two rather inconspicuous constellations that lie on, or close to, the meridian at this time.Astronomy for Young Folks|Isabel Martin Lewis
Triangulum is a very ancient constellation, being formerly named Deltoton, from the Greek letter Delta Δ.A Field Book of the Stars|William Tyler Olcott