Lewis & Short

† plēctrum, i, n., = πλῆκτρον (an instrument to strike with; esp.),

  1. I. A little stick with which the player struck the chords of a stringed instrument, a quill, plectrum: itaque plectri similem linguam nostri solent dicere, chordarum dentis, naris cornibus illis qui resonant, etc., Cic. N. D. 2, 59, 149; Ov. M. 11, 168: plectra movere, id. H. 3, 113.
    1. B. Poet., transf., a lyre or lute; also a lyric poem, lyric poetry: plectro modulatus eburno, Tib. 3, 4, 39: et te sonantem plenius aureo, Alcaee, plectro, Hor. C. 2, 13, 26; 2, 1, 40; 1, 26, 11.
  2. II. A helm, rudder (poet.): non plectro ratis Parcitur, Sil. 14, 549; 403.