The term 'at right angles' is used to describe a type of angle in which two lines intersect at a 90 degree angle. This term can be described using four different crossword solutions: abeam (5 letters), PERPENDICULAR (13 letters), orthogonal (10 letters), and ELLS (4 letters). Abeam is an adverb meaning 'in a line with the side of a ship', while PERPENDICULAR is an adjective meaning 'at right angles to a given line or plane'. Orthogonal is an adjective meaning 'at right angles to each other', and ELLS is a noun referring to a unit of measurement equal to 45 degrees.