Lewis & Short

alternus, a, um, adj. [alter], one after the other, by turns, interchangeable, alternate (class. and also poet.).

  1. I. In gen.: (Sem)VNIS. ALTERNEI. ADVOCAPIT. CONCTOS (i. e. Semones alterni advocate cunctos), Carm. Fr. Arv. 36 (v. advoco fin.): alternā vice inire, Enn. ap. Charis. p. 214 P. (Trag. v. 151 Vahl.): alternae arbores, Plaut. Trin. 2, 4, 138: Alterno tenebras et lucem tempore gigni, Lucr. 5, 978: ex duabus orationibus capita alterna recitare, Cic. Clu. 51, 140: alternis trabibus ac saxis, with beams and stones regularly interchanged, Caes. B. G. 7, 23 Herz.: (bibere) alternis diebus modo aquam, modo vinum, Cels. 3, 2: Alterno terram quatiunt pede, Hor. C. 1, 4, 7: per alternas vices, Ov. P. 4, 2, 6: vix hostem, alterni si congrediamur, habemus, Verg. A. 12, 233; 6, 121: alternum foedus amicitiae, Cat. 109, 6: alternus metus, mutual or reciprocal fear, Liv. 26, 25; cf. id. 23, 26: alternas servant praetoria ripas, the opposite, Stat. S. 1, 3, 25: aves, the eagles which stand opposite to each other, Claud. Mall. Theod. prol. 16 (v. the passage in its connection): alternis paene verbis T. Manlii factum laudans, with almost every other word, Liv. 8, 30: alternis dicetis; amant alterna Camenae, responsive song, Verg. E. 3, 59: versibus alternis, Hor. Ep. 2, 1, 146: alternis aptum sermonibus, alternate discourse, i. e. dialogue, id. A. P. 81.
    Of verses: interchanging between hexameter and pentameter, elegiac: pedes alternos esse oportebit, Cic. de Or. 3, 50, 193: epigramma alternis versibus longiusculis, id. Arch. 10, 25; Ov. H. 15, 5: canere alterno carmine, id. F. 2, 121; so id. Tr. 3, 1, 11; 3, 1, 56; 3, 7, 10 (cf.: modos impares, id. ib. 2, 220).
  2. II. Esp., in the Roman courts of justice the accused, and afterwards the accuser, could alternately reject all the judges appointed by the prætor; hence, alterna consilia or alternos judices reicere, to reject by turns, Cic. Vatin. 11, 27; id. Planc. 15, 36: cum alternae civitates rejectae sunt, id. Verr. 2, 2, 13.
    Comp. and sup. are not used.
    Advv. (only in posit.).
        1. a. Form alter-nē, alternately, only in Sen. Q. N. 7, 12 med.
        2. b. Form alternìs (abl. plur.; sc. vicibus), alternately, by turns (poet. and prose; freq. in Lucr.; not in Cic.), Lucr. 1, 524; 1, 768; 1, 1011; 1, 1066; 3, 373; 4, 790; 6, 570; Varr. R. R. 3, 16, 9; Verg. E. 3, 59; id. G. 1, 71; 1, 79; Liv. 2, 2 med.; Sen. Ep. 120 fin.; Plin. Ep. 18, 2.
        3. * c. Form alternă, neutr. plur., Plin. 11, 37, 51, § 138 Jan; App. M. 10, p. 247, 8 Elm.