Lewis & Short

co-gnosco, gnōvi, gnĭtum, 3 (tempp. perff. contr. cognosti, Ter. And. 3, 4, 7: cognostis, id. Hec. prol. 8: cognoram, Cic. de Or. 1, 31, 143; Cat. 66, 26: cognoro, Cic. Att. 7, 20, 2; id. Fam. 2, 11, 2 fin.: cognorim, Cael. ap. Cic. Att. 10, 9, A, 1: cognoris, Ter. Phorm. 2, 1, 35; Lucr. 6, 534: cognorit, Ter. Eun. 5, 4, 11: cognosses, Cic. Fl. 21, 51; Cat. 91, 3: cognossent, Nep. Lys. 4 fin.: cognosse, Lucr. 1, 331; Cat. 90, 3; Ov. M. 15, 4 al.; v. Neue, Formenl. 2, 532; 2, 535), v. a. [nosco].

  1. I. To become thoroughly acquainted with (by the senses or mentally), to learn by inquiring, to examine, investigate, perceive, see, understand, learn; and, in tempp. perff. (cf. nosco) to know (very freq. in all periods and species of composition); constr. with acc., with acc. and inf., or a rel.-clause as object, and with ex, ab, the abl. alone, or per, with the source, etc., of the information, and with de.
    1. A. By the senses: credit enim sensus ignem cognoscere vere, Lucr. 1, 697; 6, 194; Enn. Ann. ap. Pers. 6, 9 (v. 16 Vahl.); cf.: doctas cognoscere Athenas, Prop. 1, 6, 13; so, regiones, Caes. B. G. 3, 7: domos atque villas, Sall. C. 12, 3: Elysios campos, etc., Tib. 3, 5, 23: totum amnem, Verg. A. 9, 245: sepulcra, Suet. Calig. 3: Aegyptum proficisci cognoscendae antiquitatis, Tac. A. 2, 59; cf. Nep. Att. 18, 1: infantem, Suet. Calig. 13: si quid dignum cognitu, worth seeing, Suet. Aug. 43 rem, Lucil. ap. Non. p. 275, 22: ab iis Caesar haec dicta cognovit, qui sermoni interfuerunt, Caes. B. C 3, 18 fin.: si tantus amor casus cognoscere nostros.. Incipiam, Verg A. 2, 10: verum, quod institui dicere, miserias cognoscite sociorum, Cic. Verr. 2, 2, 27, § 65: aliquid et litteris et nuntiis cognoscere, id. Fam. 1, 5, 1; 14, 5, 1; 14, 6 init.: iter ex perfugis, Sall. C. 57, 3; id. J. 112, 1 al: per exploratores cognovit, Caes. B. G. 1, 22; 5, 49; 2, 11; 7, 16: deditio per nuntios cognita, Sall. H. Fragm. 2, 22 Gerl.: de Marcelli salute, Cic Fam. 4, 4, 3: de Bruto, id. Att. 5, 21, 10; Sall J. 73, 1: his (quibus) rebus cognitis very freq. in the historians, Caes. B G. 1, 19, 1, 33; 2, 17; 4, 30 et saep., so in abl. absol. cognito, vivere Ptolemaeum, Liv. 33, 41, 5, so id. 37, 13, 5, 44, 28, 4 al.; v. Zumpt, Gram. § 647.
        1. b. Like the Engl. to know, the Heb. [??] (v. Gesen. Lex. s. h. v 3), and the Gr. γιγνώσκω (v. Lidd. and Scott, under the word, III.), euphem of sexual intercourse, Ov. H. 6, 133 aliquam adulterio, Just 5, 2, 5, 22, 1, 13: cognita, Cat 61, 147; Tac. H 4, 44.
    2. B. Mentally, to become acquainted with, learn, recognize, know: nihil certum sciri, nihil plane cognosci et percipi possit, Cic. de Or 1, 51, 222, Lucr 2, 840; quod Di vitiaci fratris summum in populum Romanum studium cognoverat, Caes. B. G 1, 19; cf. Sall. C. 51, 16 quem tu, cum ephebum Temni cognosses, Cic. Fl. 21, 51 et saep.: id se a Gallicis armis atque insignibus cognovisse, knew by their weapons and insignia (diff. from ex and ab aliquo, to learn from any one, v ab), Caes. B G. 1, 22; Ov. P 2, 10, 1; Phaedr. 4, 21, 22.
      With acc. and inf: nunc animam quoque ut in membris cognoscere possis esse, Lucr 3, 117; cf. Auct. Her. 4, 18, 25: cum paucitatem mililum ex castrorum exiguitate cognosceret, Caes B G. 4, 30: aetatem eorum ex dentibus, Varr R. R. 2, 8 fin.: sed Metello jam antea experimentis cognitum erat, genus Numidarum infidum … esse, Sall. J 46, 3 al.
      With acc. and part.: aliter ac sperarat rempublicam se habentem, Nep. Ham. 2, 1.
      With rel.- clause: tandem cognosti qui siem, Ter And. 3, 4, 7: id socordiāne an casu acciderit, parum cognovi, Sall. J. 79, 5 al.
  2. II. To recognize that which is already known, acknowledge, identify (rare for agnosco): vereor, ne me quoque, cum domum ab Ilio cessim revertero, Praeter canem cognoscat nemo, Varr. ap. Non. p. 276, 9: eum haec cognovit Myrrhina, Ter. Hec. 5, 3, 32: primum ostendimus Cethego signum: cognovit, Cic. Cat. 3, 5, 10; cf.: sigilla, ova, id. Ac. 2, 26, 86; Lucr. 2, 349: pecus exceptum est, quod intra dies XXX. domini cognovissent, to identify, Liv. 24, 16, 5; cf.: ut suum quisque per triduum cognitum abduceret, id. 3, 10, 1; Ov. F. 2, 185: video et cognosco signum, Plaut. Ps. 4, 2, 45: faciem suam, Ov. A. A. 3, 508: cognito regis corpore, Just. 2, 6, 20: mores, Ov. P. 3, 2, 105.
    So esp., to identify a person before a tribunal: cum eum Syracusis amplius centum cives Romani cognoscerent, Cic. Verr. 2, 1, 5, § 14; 2, 5, 28, § 72.
  3. III. With the access. idea of individual exertion (cf. Gr. γιγνώσκω), to seek or strive to know something, to inquire into, to investigate, examine (so freq. only as a jurid. and milit. t. t.): accipe, cognosce signum, Plaut. Ps. 4, 2, 31.
    1. A. Jurid. t. t., to examine a case in law, to investigate judicially (cf. cognitio): Verres adesse jubebat, Verres cognoscebat, Verres judicabat, Cic. Verr. 2, 2, 10, § 26; cf. Quint. 4, 2, 21; Dig. 13, 4, 4 al.
      So absol.: si judicas, cognosce, Sen. Med. 194.
      With acc.: causam, Quint. 4, 1, 3; cf. id. 11, 1, 77 Spald. N. cr.: causas, Cic. Off. 2, 23, 82; id. Verr. 2, 2, 48, § 118. COGNITIONES, Inscr. Orell. 3042.
      With de: de agro Campano, Cic. Phil. 5, 19, 53: de Caesaris actis, id. Att. 16, 16 B, 8: de hereditate, id. Verr. 2, 2, 7, § 19: hac de re, id. ib. 2, 1, 10, § 27; cf. Quint. 6, 3, 85; 7, 4, 35; 8, 3, 62 al.; Suet. Aug. 55; 93; id. Tib. 33; id. Calig. 38 al.: super aliquā re, Dig. 23, 2, 13: familiae herciscundae, i. e. ex actione familiae herciscundae, ib. 28, 5, 35; cf. ib. 27, 2, 2.
      1. 2. Transf., of critics and the criticising public: cognoscere atque ignoscere, Quae veteres factitarunt, si faciunt novi, Ter. Eun. prol. 42; cf. id. Hec. prol. 3 and 8.
        And of private persons in gen.: et cognoscendi et ignoscendi dabitur peccati locus, Ter. Heaut. 2, 1, 6.
    2. B. Milit. t. t., to reconnoitre, to act the part of a scout: qualis esset natura montis et qualis in circuitu ascensus, qui cognoscerent, misit, Caes. B. G. 1, 21 al
      Also merely to inquire into, examine: numerum tuorum militum reliquiasque, Cic. Pis. 37, 91 (al. recognoscere).
      Hence,
      1. * 1. cognoscens, entis, P. a., acquainted with: cognoscens sui, Auct. Her. 4, 18, 25.
        Subst. in jurid. lang., one who investigates judicially Inscr Orell 3151; 3185.
        * Adv.: cognoscenter, with knowledge, distinctly: ut cognoscenter te videam, Tert. adv. Marc. 4, 22.
      2. 2. cognĭtus, a, um, P. a., known, acknowledged, approved. res penitus perspectae planeque cognitae, Cic. de Or. 1, 23, 108, cf. id. ib 1, 20, 92; id. Fam. 1, 7, 2. dierum ratio pervulgata et cognita, id. Mur 11, 25: homo virtute cognitā et spectatā fide, id. Caecin. 36, 104.
        With dat.: mihi Galba, Otho, Vitellius nec beneficio nec injuriā cogniti, Tac. H. 1, 1, so Plin. 12, 21, 45, § 99.
        Comp.: cognitiora, Ov Tr. 4, 6, 28. cognitius, id. M. 14, 15.
        Sup.: cognitissima, Cat. 4, 14.