Lewis & Short

agmĕn, ĭnis, n. [as if contr. from agimen, from ago; cf.: tegimen, tegmen, from tego].

  1. I. Lit.
    1. A. In gen., a train, i. e. a collected multitude in motion or moving forwards; of things of any kind, but esp. (so most freq. in prose) of men or animals.
      Of streams of water, motion, course, current: quod per amoenam urbem lent fluit agmine flumen, Enn. ap. Macr. S. 6, 4: inde super terras fluit agmine dulci, Lucr. 5, 272; cf. id. 6, 638; also, in imitation of Enn., Virg. and Val. Fl.: leni fluit agmine Thybris, Verg. A. 2, 782; cf. Val. Fl. 4, 721.
      Of a train or succession of clouds: denso sunt agmine nubes, Lucr. 6, 100.
      Of rain: immensum caelo venit agmen aquarum, body, mass, Verg. G. 1, 322
      Of atoms: agmine condenso naturam corporis explent, crowded into a compact mass, Lucr. 1, 607.
      Of oars: agmine re morum ceieri, with quick plashing of oars, Verg. A. 5, 211.
      Of a flock of birds: agmi ne magno. Corvorum. Verg. G. 1, 381.
      Of a snake winding onwards: cum medii nexus extremaeque agmina caudae Solvuntur, Verg. G. 3, 424; cf. id. A. 2, 212.
      Of clouds of dust following any thing in rapid motion, as men, animals, etc.: agmina cervi Pulverulenta, Verg. A. 4, 154.
      And, as subst. concr., of birds turba Agminis aligeri, of the winged band, Verg A. 12, 249.
      Of ants; frugilegas aspeximus agmine longo formi cas, Ov. M 7, 624; so id. ib. 7, 638.
      Of the stars: diffugiunt stellae; quarum agmina cogit Lucifer, Ov. M. 2, 114; so id. ib. 11, 97 al.
      Eap. of a company of persons, a multitude, troop, crowd, number, band: ut a Brundisic nsque Romam agmen perpetuum totius Italiae viderem, Cic. Pis. 22: magno senatorum agmine, Tac. H. 3, 55: ingens mulierum agmen, Liv. 2, 40: muliebre et miserabile agmen, Tac. A. 1, 40: numerosum agmen reorum, Plin Ep. 3, 9, and Tac. H. 4, 6: Eumenidum agmina, Verg A. 4, 469.
      But particularly,
    2. B. The train, procession, march, progress of an army: de castris, de agminibus, etc., dicere, Cic. de Or. 1, 48, 210: ne miles gregarius in castris, neve in agmine servum aut jumentum haberet, Sall. J. 45, 2: pugnatum saepe directā acie, saepe in agminibus, saepe eruptionibus, Vell. 2, 47: effuso agmine abire, Liv. 44, 39: uno agmine victores cum victis in urbem irrupere, id. 2, 30; uno agmine persequentes, Vulg. Judith, 15, 4 al.
  2. II. Transf., concr., an army, and properly considered as in motion, on the march (while exercitus is a disciplined army, and acies an army in battle-array)
    As soon as the signal for marching was given, the Extraordinarii and the allies of the right wing, with their baggage, first put themselves in motion, then the legions, and last the allies of the left wing, with a part of the cavalry, which either rode behind the army, ad agmen claudendum or cogendum. to close the train, i. e. to keep it to gether or on the side in such an order (composito agmine, non itineri magis apto quam proelio) that it might be easily put into the line of battle, if the enemy ven tured to attack it; cf. Sall. J. 46, 6.
    An army in close ranks was called agmen justum, Tac. H. 1, 68, or agmen pilatum, Serv. ad Verg. A. 12, 121
    When there was no apprehension of the enemy, less care was taken for the protection of the army: agmine incauto, i. e. minus munito, ut inter pacatos, ducebat, sc. consul, Liv. 35, 4.
    The order of march was, however, different, according to circumstances and the nature of the ground, Liv. 35, 4; 27, 28; and cf. Smith’s Antiq.
    Sometimes the army marched in the form of a square, agmen quadratum, with their baggage in the middle, so as to be in battle-array on meeting the enemy; hence agmen quadratum often means the same as acies triplex, an army formed in line of battle, only that the former indicates that they are on the march, and the latter that they are at rest.
    Hence, like acies, with the epithet primum, the vanguard, Liv. 34, 28; Tac. Agr. 35: medium, the centre, Liv. 10, 41; Tac. H. 4, 22: extremum, Liv. 34, 28; Tac. H. 2, 100; or, novissimum, the rear, rearguard, Liv. 44, 33; so, extremi agminis, Vulg. Deut. 25, 18: ut inde agmine quadratc ad urbem accederet, marching in a square, Cic. Phil. 13, 8: pariter atque in conspectu hostium quadrato agmine incedere, Sall. J 100, 1; cf. id. ib. 46, 6, 7: Hannibal agmine quadrato amnem ingressus, Liv. 21, 5; se id. 31, 36; 37, 39: quadrato agmine velut in aciem irent, Curt. 5, 1, 19 al.
    Sometimes, esp. in the poets in the plur., in gen. sense, = exercitus or copiae, an army, host, troops: huic tanto agmini dux defuit, Just. 12, 10: occidit Daci Cotisonis agmen, Hor. C. 3, 8, 18: agmina curru Proterit, Verg. A. 12, 329: barbarorum Claudius agmina diruit, Hor. C. 4, 14, 29; so id. S. 2, 1, 14; id. Epod. 17, 9; Ov. M. 3, 535; 5, 151, 161; 6, 423: Del agminum Israël, Vulg. 1 Reg. 17, 45: agmina ejus dispergam, ib. Ezech. 12, 14; 38, 6.
    For military service, warfare: rudis agminum Sponsus, Hor. C. 3, 2, 9.
    1. B. Trop.
      1. 1. An army, troop, band, multitude: educenda dictio est ex hac domesticā exercitatione et umbratili medium in agmen, in pulverem, in clamorem, in castra, aciemque forensem, i. e. before the public, Cic. de Or. 1, 34, 157: e Brundisio usque Romam agmen perpetuum totius Italiae, an unbroken train, id. Pis. 22, 51: ingens mulierum agmen, Liv. 2, 40; 9, 17: agmina Eumenidum, Verg. A. 4, 469; 6, 572: agmina comitum, Ov. Tr. 14, 30: in angusto fidus comes agmine turbae, Tib. 1, 5, 63: numerosum agmen reorum, Plin. Ep. 3, 9: agmen occupationum, an army of, id. ib. 2, 8.
      2. 2. March, movement: agmina fati et volumina, Gell. 6, 2, 5.