Lewis & Short

nervĭae, ārum, f., and nervĭa, ōrum, n. [cf. nervus],

  1. I. strings or chords of a musical instrument, gut-strings, Varr. ap. Non. 215, 15; Gell. 9, 7, 3.
  2. II. Transf., nerves, Varr. ap. Non. 215, 16 (Sat. Men. 63, 4); Petr. 45, 11.