any of several muscles that cause an attached structure to become tense or firm
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Tensor \Ten"sor\, n. [NL. See {Tension}.] 1. (Anat.) A muscle that stretches a part, or renders it tense.
2. (Geom.) The ratio of one vector to another in length, no regard being had to the direction of the two vectors; -- so called because considered as a stretching factor in changing one vector into another. See {Versor}.
In 1912, however, a mathematician friend, Marcel Grossman, introduced him to tensor calculus.