The Collaborative International Dictionary
Amblygon
Amblygon \Am"bly*gon\, n. [Gr. ? obtuse + ? angle: cf. F. amblygone.] (Geom.) An obtuse-angled figure, esp. and obtuse-angled triangle.
Wiktionary
amblygon
n. (context geometry obsolete rare English) An obtuse-angled figure, especially a triangle.