Entry 2 senses · 2 variants Webster, 1913 Rectangle /(r?k"t??`g'l)/ · Rec·tan·gle · IPA /ˈrɛktæŋɡl̩/ n. a. 01 n. A four-sided figure having only right angles; a right-angled parallelogram. 1. A four-sided figure having only right angles; a right-angled parallelogram.(Geom.) 02 a. Rectangular. 1. Rectangular.[R.]