A.multiply by three, Plu.2.416b (Pass.).
2. represent as a triangular number, Nicom.Ar.2.8 (Pass.).
II. intr., to be triangular, “νῆσος τριγωνίζουσα” Hld.10.5:—Pass., “τετριγωνίσθαι” assume triangular form, Plot.2.6.2; “ὁ ὀδοὺς -ίζεται” Hippiatr.95.