hypotenuse: [16] The hypotenuse is etymologically a line that is ‘stretched under’ the right angle of a triangle. The word comes via Latin hypotēnūsa from Greek hupoteínousa, a derivative of hupoteínein. This was a compound verb formed from the prefix hupo- ‘under’ and teínein ‘stretch’ (a relative of English tend, tense, etc). => tend, tense
