Lewis & Short

sub-nŏto, āvi, ātum, 1, v. a. (post-Aug.).

  1. I. To mark, note, or write underneath (cf. subscribo): in inferiori lineā particulares propositiones subnotentur, App. Dogm. Plat. 3, p. 31, 27: nomina palam, to write down, Suet. Calig. 41.
    Transf.: libellos, to subscribe, Plin. Ep. 1, 10, 9.
  2. II. To note secretly, to mark, watch, observe: et non sobria verba subnotasti, Mart. 1, 28, 5: aliquem vultu digitoque, id. 6, 82, 3.