Lewis & Short

impressĭo (inpr-), ōnis, f. [imprimo], a pressing into, an impressing, impression (class.).

  1. I. Lit.
    1. A. In gen.: materiam signari impressione formarum, App. Dogm. Plat. 1, p. 4: signaculi, Schol. Juv. 1, 68: nummorum, stamping, coining, Aug. Doctr. Christ. 2, 25.
    2. B. In partic.
      1. 1. An irruption, inroad, onset, assault, attack: non judicio neque disceptatione, sed vi atque impressione (aliquem) evertere, Cic. Fam. 5, 2, 8; id. Fl. 34, 85: hostes arbitrati occasionem se habere victoriae impressionem facere coeperunt, Varr. R. R. 2, 4. 1; cf.: ut omni multitudine in fines Suessionum facerent impressionem, Hirt. B. G. 8, 6, 2; Liv. 4, 28, 6; 8, 9, 3; 25, 37, 13.
      2. 2. A pressure, rough or violent handling: omnis impressio et tumentia provocat et dolorem geminat, Cael. Aur. Acut. 3, 8, 92.
      3. 3. A squeezing, pressure of a multitude, Fronto, Ep. ad M. Caes. 5, 30 Mai.
  2. II. Trop.
    1. A. Of speech, a division: si numerosum est id in omnibus sonis et vocibus, quod habet quasdam impressiones et quod metiri possumus intervallis aequalibus, divisions of time, beats, Cic. de Or. 3, 48, 185.
    2. B. Transf., a marked expression, emphasis: in lingua explanata vocum impressio, Cic. Ac. 1, 5, 19.
    3. C. The impression on the mind made by phenomena: cum visa in animis imprimantur, non vos id dicere, inter ipsas impressiones nihil interesse, sed inter species et quasdam formas eorum, Cic. Ac. 2, 18, 58.