Lewis & Short

inter-sum, fŭi, esse (interfŭtūrus, Cic. Div. in Caecil. 11, 35; in tmesi: interque esse desiderat pugnis, Arn. 7, 255), v. n., to be between, lie between (class.; syn. interjaceo).

  1. I. In gen.
    1. A. Of space: quas (segetes) inter et castra unus omnino collis intererat, Caes. B. G. 6, 35: ut Tiberis inter eos et pons interesset, Cic. Cat. 3, 2: via interest perangusta, Liv. 22, 4: morari victoriam rati, quod interesset amnis, id. 21, 5: quod interest spatii, Plin. 6, 9, 10, § 28.
    2. B. Of time: cujus inter primum et sextum consulatum sex et quadraginta anni interfuerunt, elapsed, Cic. de Sen. 17, 60: inter Laviniam et Albam Longam coloniam deductam triginta ferme interfuere anni, Liv. 1, 3; Cic. Leg. 3, 3, 8.
  2. II. Transf.
    1. A. To be apart; with abl. of distance (syn. disto): clathros interesse oportet pede, Cato, R. R. 4.
    2. B. To be different, to differ: ut inter eos, ne minimum quidem intersit, there is not the slightest difference, Cic. Ac. 2, 17, 52: inter hominem et beluam hoc maxime interest, quod, men differ chiefly from brutes in this, that, etc., id. Off. 1, 4, 11: vide, quantum interfuturum sit inter meam atque tuam accusationem, how great a difference there will be, id. Div. in Caecil. 11, 35: in his rebus nihil omnino interest, there is no difference whatever, id. Ac. 2; 15, 47: hoc pater ac dominus interest, there is this difference, Ter. Ad. 1, 1, 51: tantum id interest, veneritne eo itinere ad urbem, an ab urbe in Campaniam redierit, Liv. 26, 11.
      With ab (like differo, rare): negant quidquam a falsis interesse, Cic. Ac. 2, 9, 27; cf.: quod intersit aut differat, aliud ab alio, id. Fin. 3, 7, 25: quod ab eo nihil intersit, etc., id. Ac. 2, 26, 83.
      With dat.: ut matrona Intererit Satyris paulum pudibunda protervis, Hor. A. P. 232: quid dimidium dimidiato intersit, Gell. 3, 14, 4.
      With gen. (in analogy with the Gr. διαφέρειν τινός): quoniam τὸ νεμεσᾶν interest (= διαφέρει) τοῦ φθονεῖν, i. e. anger differs from envy, Cic. Att. 5, 19 fin.
    3. C. To be present at, take part in, attend; constr. absol., with dat. or in and abl.
          1. (α) Absol.: ac si ipse interfuerit, ac praesens viderit, Cic. Inv. 1, 54, 104: interfuisse me memini, Suet. Dom. 12.
          2. (β) With dat. rei: consiliis, Cic. Att. 14, 22, 2; 2, 23, 3: crudelitati, id. ib. 9, 6, 7: negotiis, id. Fam. 1, 6: lacrimis patris, Verg. A. 11, 62: ludis, Suet. Tib. 72: caedi, id. Dom. 47: rebus gerendis, Gell. 5, 18, 1: sermoni, id. 11, 7, 1: senatui, Cic. Dom. 11; Suet. Claud. 46: populo Quirini, to be among, live with, Hor. C. 1, 2, 46: rebus divinis, Caes. B. G. 6, 13, 4: proelio, id. ib. 7, 87: bello, Liv. 36, 4: spectaculo, id. 2, 38.
            Also, with dat. loci: curiae, Suet. Aug. 38: contubernio patris, Aur. Vict. Caes. 27, 1.
            Also, with dat. pers.: sacrificanti interfuit, attended him, Suet. Oth. 6.
          3. (γ) With in and abl.: in convivio, Cic. Rosc. Am. 14, 39: in testamento faciendo, id. Clu. 59, 162: voluerunt eos in suis rebus ipsos interesse, id. Verr. 2, 3, 6, § 14: quibus in rebus, Auct. Her. 1, 9.
            Also used of time, to live in: quisquis illis temporibus interfuit, Vell. 2, 114, 2: cui tempori Saturninus interfuit, Sulp. Sev. Dial. 3, 3; cf.: ea (ratiocinatio) dicitur interfuisse tum, cum aliquid vitasse aut secutus esse animus videbitur, to have taken place, Cic. Inv. 2, 5, 18.
    4. D. To interest, be of interest to one (very rare as pers. verb): non quo mea interesset natura loci, Cic. Att. 3, 19, 1 (cf. interest, impers. infra).
  3. III. Esp.: intĕrest, impers., it makes a difference, interests, concerns, imports; is of interest, importance; constr. with gen. pers. or meā, tuā, suā, and with a subj. or rel. clause, ut or ne, or with ad: ea vos rata habeatis, ne magis reipublicae interest, quam mea, Liv. 26, 31, 10: quanto opere reipublicae communisque salutis intersit, manus hostium distineri, Caes. B. G. 2, 5, 2: semper ille, quantum interesset P. Clodii, se perire, cogitabat, Cic. Mil. 21, 56: quid illius interest, ubi sis? id. Att. 10, 4, 10: quis enim est hodie, cujus intersit istam legem manere? id. Phil. 1, 9: hoc vehementer interest rei publicae, id. Q. Fr. 2, 4, 1: quod ego et mea et rei publicae interesse arbitror, id. Fam. 2, 19 fin.: multum interest rei familiaris tuae, te quam primum venire, id. Fam. 4, 10, 2: tuā et meā maxime interest, te valere, id. ib. 16, 4: id ignorare eos velis, quorum intersit id scire, id. Off. 3, 13, 57.
    With ut or ne: illud meā magni interest, te ut videam, Cic. Att. 11, 22, 2: quod ut facias tuā interesse arbitror, id. Fam. 12, 18, 2: vestrā interest, ne imperatorem pessimi faciant, Tac. H. 1, 30: non tam suā quam reipublicae interesse ut salvus esset, Suet. Caes. 86; so, utriusque nostrum magni interest ut te videam, Cic. Fam. 3, 5, 4 B. and K. (dub.).
    With gen. pretii: quod meus familiaris tanti suā interesse arbitraretur, Cic. Fam. 13, 10.
    With rel. or interrog.-clause: in omnibus novis conjunctionibus interest, qualis primus aditus sit, Cic. Fam. 13, 10, 4: non tam interest, quo animo scribatur, quam quo accipiatur, Caecin. ap. Cic. Fam. 6, 7, 1: neque multum interest, quod nondum per numeros distributi sunt, Plin. Ep. 10, 30, 2; cf. with utrum … an: quid interfuit, homo audacissime, utrum hoc decerneres, an, etc., what mattered it? Cic. Verr. 2, 3, 61, § 141: nihil interest nunc, an violaverim, etc., Liv. 26, 31.
    With ad: ad honorem interesse, Cic. Fam. 16, 1, 1: ad decus et ad laudem civitatis, id. N. D. 1, 4, 7: ad laudem nostram, id. ib. 5, 12, 2: ad beate vivendum, id. Fin. 2, 28, 90.