1530s, "a stretched condition," from French tension (16c.) or directly from Latin tensionem (nominative tensio) "a stretching" (in Medieval Latin "a struggle, contest"), noun of state from tensus, past participle of tendere "to stretch," from PIE root *ten- "to stretch." The sense of "nervous strain" is first recorded 1763. The meaning "stress along lines of electromotive force" (as in high-tension wires) is recorded from 1785.
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<a href="https://www.etymonline.com/word/hypertension">Etymology of hypertension by etymonline</a>
Harper, D. (n.d.). Etymology of hypertension. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/hypertension