[a. mod.L. tensor, agent-n. from tendĕre to stretch.]
1. Anat. (also tensor muscle): A muscle that stretches or tightens some part. Opp. to laxator.
In mod. use, distinguished from an extensor by not altering the direction of the part.
1704. J. Harris, Lex. Techn., I. Tensors, or Extensors, are those common Muscles that serve to extend the Toes, and have their Tendons inserted into all the lesser Toes.
1799. Home, in Phil. Trans., XC. 10. The combined action of the tensor and laxator muscles varying the degree of its [the membrana tympani] tension.
1808. Barclay, Muscular Motions, 384. The biceps … being a flexor and supinator of the fore-arm, and at the same time a tensor of its fascia.
1879. St. George’s Hosp. Rep., IX. 591. The functions of the adductors and tensors are more delicate.
2. Math. In Quaternions, a quantity expressing the ratio in which the length of a vector is increased.
1853. Hamilton, Elem. Quaternions, II. i. (1866), 108. The former element of the complex relation … between … two lines or vectors [viz. their relative length], is … represented by a simple ratio…, or by a number expressing that ratio. Note, This number, which we shall … call the tensor of the quotient,… may always be equated … to a positive scalar.
1886. W. S. Aldis, Solid Geom., xiv. (ed. 4), 235. Since the operation denoted by a quaternion consists of two parts, one of rotating OA into the position OB and the other of extending OA into the length OB, a quaternion may be … represented as the product of two factors,… the versor … and … the tensor of the quaternion.
b. Comb., as tensor-twist, in Clifford’s biquaternions, a twist multiplied by a tensor.
