"Triangled" is a word that doesn't actually exist in standard English. However, it could be spelled as "triangular", pronounced /traɪˈæŋɡjʊlər/ (try-ANG-gyuh-lur) with stress on the second syllable. This word means having three sides or corners, like a triangle. The "-ar" at the end of the word comes from the Latin suffix "-aris", which indicates association or possession. The correct spelling and pronunciation of words is important for clear communication and helps to avoid confusion.
Having the form of a triangle; formed into triangles.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.