sinews

/S IH1 N Y UW0 Z/
noun
  1. 1

    A cord or tendon of the body.

  2. 2

    A cord or string, particularly as of a musical instrument.

  3. 3

    Muscular power, muscle; nerve, nervous energy; vigor, vigorous strength.

  4. 4

    (often in the plural) That which gives strength or in which strength consists; a supporting factor or member; mainstay.

  5. 5

    A nerve.

Source: https://en.wiktionary.org/wiki/sinew, https://en.wiktionary.org/wiki/sinews