Lewis & Short

tactĭo, ōnis, f. [tango].

  1. I. Lit., a touching, touch (Plautin.), as a verbal noun with acc.: quid tibi hanc digito tactio est? Plaut. Poen. 5, 5, 29; id. Aul. 3, 2, 9; 4, 10, 14; id. Cas. 2, 6, 56; id. Curc. 5, 2, 27.
  2. * II. Transf., the sense of touch, feeling: oculorum et tactionum et odorationum et saporum (voluptates), Cic. Tusc. 4, 9, 20.