Printable Version
Pronunciation: hai-paht-n-yus Hear it!

Part of Speech: Noun

Meaning: The longest side of a right triangle, opposite the right angle.

Notes: Today's word started its life as a rigidly mathematical term. It was so busy carrying its mathematical cargo that it had no time to raise a family of derivations. It has but one rarely seen relative, the adjective hypotenusal.

In Play: This word has traditionally been the property of the field of mathematics: "If the area of a right triangle is 150 square feed, its hypotenuse is 25 feet." However, recently it has eluded this field to be used figuratively in other contexts: "Phil Anders must always be the hypotenuse of his love triangles."

Word History: Today's word comes from French hypoténuse, inherited from Latin hypotenusa, which borrowed it from Greek hypoteinousa "stretching under", the feminine present participle of hypoteinein "to stretch under", made up of hypo "under, beneath" + teinein "to stretch". Greek hypo was a revision of PIE (s)upo "under, up from under, over" with a Fickle S, that also provided the basic materials for Greek hyper "over", Latin super "over" and English up. Greek teinein "to stretch" came from PIE ten- "to stretch", which also provided Greek with tetanos "rigid, stiff", tenon "tendon", and tonos "string". English borrowed relatives of all three of these words as tetanus, tendon, and tone. English tenor was a Latin word based on the same PIE root. (Today we thank William Hupy for finding a usually technical Good word with an interesting history and figurative use.)

Dr. Goodword,

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