hypotenuse The longest side of a right triangle – the one opposite the right angle. The word comes from the Greek roots hypo meaning "under" (which also appears, for example, in hypodermic – "under the skin") and tein or ten, for stretch. Thus hypotenuse is the line segment "stretched under" the right angle. Related category GEOMETRY Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) |