Lewis & Short

prĭor and prĭus (old form also in neutr. prior, Val. Antias and Quadrig. ap. Prisc. p. 767), ōris, adj. comp. [from obsol. prep. pri; v. primus init.], former, previous, prior, freq. to be translated first; cf. superior; Cicero nearly always uses prior, opp. to posterior, in time; superior in sense of former, in gen. relation to the present, when no other time is expressed; v. Krebs, Antibarb. p. 921 sq.

  1. I. Lit.: ita priori posterius, posteriori superius non jungitur, Cic. Ac. 2, 14, 44: me quaestorem in primis, aedilem priorem, praetorem primum populus Romanus faciebat, id. Pis. 1, 2: qui prior has angustias occupaverit, first, Caes. B. C. 1, 66: prior proelio lacessere, id. ib. 1, 82: etsi utrique primas, priores tamen libenter deferunt Laelio, Cic. Brut. 21, 84: priore loco causam dicere, first, id. Quint. 9, 32: priore aestate, in the former summer, last summer, id. Fam. 1, 9, 24: priore nocte, id. Cat. 1, 4, 8: factum est enim meā culpā, ut priore anno non succederetur, id. Q. Fr. 1, 1, 1, § 2: prioribus comitiis, id. Planc. 22, 54: priore anno, the year before, Liv. 3, 9, 7; 3, 10, 14; 4, 56, 5: prioris anni consules, id. 4, 13, 10; 4, 17, 9: Dionysius prior, the elder, Nep. Dion, 1, 3: vinum, of last year, Plin. 14, 19, 24, § 120: priore libro, in the previous book, Col. 4, 22, 9: pedes, the forefeet, Nep. Eum. 5, 5; Plin. 8, 45, 70, § 181: canities homini semper a priori parte capitis, tum deinde ab aversā, the forepart, Plin. 11, 37, 47, § 131.
    Pleon.: cum prior Romanus exercitus praevenisset, Liv. 9, 23, 2: prius praecepta res erat, id. 21, 32, 7; cf. id. 9, 23, 2.
    Old neutr. prior: hoc senatusconsultum prior factum est, Val. Antias ap. Prisc. p. 767 P.: prior bellum, Quadrig. ib.: foedus prior, id. ib. (cf.: bellum Punicum posterior, Cass. Hem. ib.).
      1. 2. Former, i. e. deceased (late Lat.): inter prieres fratres, Amm. 21, 6, 2.
    1. B. Subst.: prĭōres, um, m., forefathers, ancestors, the ancients (poet. and in post-Aug. prose): abiturus illuc, quo priores abierunt, Phaedr. 4, 18, 16: nomen dixere priores Ortygiam, Verg. A. 3, 693: nec ingeniis investigata priorum, Ov. M. 15, 146; 332: priores tradiderunt, Col. 1, 4, 3: nostri, Plin. Ep. 3, 4: more priorum, Ov. M. 10, 218; Sen. Ep. 52, 2.
  2. II. Trop., better, superior, preferable, more excellent or important (not in Cic. and Cæs.): bellante prior, Hor. C. S. 51: color puniceae flore prior rosae, id. C. 4, 10, 4; Ov. H. 18, 69: ut nemo haberetur prior, Liv. 27, 8: aetate et sapientiā, Sall. J. 10, 7: consilio et manu, id. ib. 96, 3: neque prius, neque antiquius quidquam habuit, quam, etc., Vell. 2, 52, 4.
    Esp. with potior: potius quanto prius potiusque est Philippum nobis conjungere quam hos, Vell. 36, 7, 6: nulla (res) prior potiorque visa est, id. 8, 29, 2: nihil prius nec potius visum, id. 39, 47, 4: unus Plinius est mihi priores, i. e. worth more than they all, Sent. Augur. ap. Plin. Ep. 4, 27, 4: artium multitudine prior omnibus, eloquentiā nulli secundus, App. Flor. 2, p. 346.
    Hence, adv. comp.: prĭus.
    1. A. Before, sooner, first, previously (class.).
      1. 1. Alone: quem fuit aequius, ut prius introieram in vitam, sic prius exire de vitā, Cic. Lael. 4, 15: regem prius Europā, post et Asiā, expellere, Liv. 37, 52, 4: ut vos prius experti estis, nunc Antiochus experitur, id. 36, 17, 8; so, priusnunc, Verg. G. 3, 362: priustum, Cato, R. R. 135; Liv. 34, 55, 5: prius . … postea, id. 29, 12, 11.
      2. 2. With quam, and often joined in one word, priusquam.
          1. (α) Before that, before: prius quam lucet, assunt, before dawn, Plaut. Mil. 3, 1, 115: prius illi erimus quam tu, id. Ps. 2, 4, 68: prius quam plane aspexit ilico eum esse dixit, id. Rud. 4, 4, 87: nihil prius mihi faciendum putavi, quam ut, etc., Cic. Att. 4, 1, 1: cui prius quam de ceteris rebus respondeo, de amicitiā pauca dicam, before, id. Phil. 2, 1, 3: quod ego, prius quam loqui coepisti, sensi, id. Vatin. 2, 4: neque prius fugere destiterunt, quam ad flumen Rhenum pervenerunt, Caes. B. G. 1, 53: quid potius faciam, prius quam me dormitum conferam, non reperio, Cic. Fam. 9, 26, 1: priusquam aggrediar, etc., id. Balb. 7, 18: prius quam ad portam venias, Ter. Ad. 4, 2, 44.
          2. (β) Sooner, rather: Aegyptii quamvis carnificinam prius subierint, quam ibin aut aspidem violent, Cic. Tusc. 5, 27, 78; id. Lig. 12, 34; Caes. B. C. 3, 1.
            Sometimes in an inverted order: ad hoc genus hominum duravi, quam prius me ad plures penetravi, Plaut. Trin. 2, 2, 13; Prop. 2, 14, 11 (3, 10, 10); v. Zumpt, Gram. § 576.
    2. B. In gen., formerly, in former times (poet.), Cat. 51, 13: sed haec prius fuere: nunc, etc., id. 4, 25; Prop. 1, 1, 18.