Lewis & Short

2. fĭdes, ium, plur., or fides, is, sing., f. [= σφίδη], a stringed instrument, lyre, lute, cithern.

  1. I. Lit.
    1. A. In gen.
          1. (α) In plur. (only so in classic prose): Fides genus citharae, Paul. ex Fest. p. 89, 16 Müll.: (hominis) omnis vultus omnesque voces, ut nervi in fidibus, ita sonant, ut a motu animi quoque sunt pulsae, Cic. de Or. 3, 57, 216; so different from nervi, id. Div. 2, 14, 33; id. Leg. 2, 15, 39; id. Brut. 54, 199; id. Fin. 4, 27, 75 (v. Madv. ad h. l., p. 601 sq.): ut in fidibus aut tibiis, atque in cantu ipso ac vocibus concentus est quidam tenendus ex distinctis sonis, etc., id. Rep. 2, 42; id. Fin. 4, 27, 75; cf. id. de Or. 3, 51, 197: Fi. Fides non reddis? Pe. Neque fides neque tibias, Plaut. Ep. 3, 4, 77; with tibiae, Quint. 1, 10, 14; 20; 11, 3, 59: Orpheus, Threïciā fretus citharā fidibusque canoris, Verg. A. 6, 120: fidibus cantare alicui, Plaut. Ep. 3, 4, 64: fidibus canere praeclare, Cic. Tusc. 1, 2, 4; id. Div. 2, 59, 122: uti, id. Tusc. 5, 39, 113: dicere longum melos, Hor. C. 3, 4, 4: placare deos, id. ib. 1, 36, 1: discere, Cic. de Sen. 8, 26: docere aliquem, id. Fam. 9, 22, 3: scire, Ter. Eun. 1, 2, 53: vivunt commissi calores Aeoliae fidibus puellae, Hor. C. 4, 9, 12: fidibusne Latinis Thebanos aptare modos studet, i. e. to imitate Pindaric odes in Latin poetry, id. Ep. 1, 3, 12.
          2. (β) Sing. (poet.): sume fidem et pharetram: fies manifestus Apollo, Ov. H. 15, 23; so, Teïa, Hor. C. 1, 17, 18: Cyllenea, id. Epod. 13, 9: quodsi blandius Orpheo moderere fidem, id. C. 1, 24, 14.
      1. 2. Prov.: vetus adagium est: Nihil cum fidibus graculo, i. e. ignoramuses have nothing to do with poetry, Gell. N. A. praef. § 19.
    2. B. Esp., Fides, is, f., a constellation, i. q. Lyra, the Lyre: cedit clara Fides Cyllenia, Cic. Arat. 381; Varr. R. R. 2, 5, 12; in the form Fidis, Col. 11, 2, 14; 40; Sid. Carm. 16, 5.
  2. * II. Transf., in sing., i. q. nervus, chorda, a string of a musical instrument: quae tuba quaeve lyra Flatibus incluta vel fidibus, Prud. Cath. 3, 81.