Lewis & Short

1. lā̆brum, i, n. [root lab, as in labium; v. lambo], a lip.

  1. I. Lit.: cape cultrum ac seca digitum vel nasum vel labrum, Plaut. Merc. 2, 2, 39: apes, quas dixisti in labris Platonis consedisse pueri, Cic. Div. 2, 31, 66: vide ut discidit labrum, Ter. Ad. 4, 2, 20: labrum superius, the upper lip, Caes. B. G. 5, 14: (poculis) labra admovere, Verg. E. 3, 43: labra movere, Hor. Ep. 1, 16, 60; Juv. 13, 114: sive puer furens impressit memorem dente labris notam, Hor. C. 1, 13, 12: haec ego mecum Compressis agito labris, id. S. 1, 4, 137: labra distorquere, Quint. 1, 11, 9: labra male porrigere, scindere, adstringere, diducere, replicare, in latus trahere, id. 11, 3, 81: labra labris conserere, to kiss, Cn. Matius ap. Gell. 20, 9, 2: labra labellis ferrummare, to kiss, Plaut. Mil. 4, 8, 25; so, labra ad labella adjungere, id. Ps. 5, 1, 14: labra valgiter commovere, Petr. 26: viscantur labra mariti, Juv. 6, 466.
    1. B. Prov.: linere alicui labra, to deceive one, Mart. 3, 42, 2: non in pectore, sed in labris habere bonitatem, Lact. 3, 16, 4: primis or primoribus labris gustare, or attingere aliquid, to get a slight taste of, to get only a superficial knowledge of a thing, Cic. N. D. 1, 8, 20: quae ipsi rhetores ne primoribus quidem labris attigissent, id. de Or. 1, 19, 87: multos vidi qui primoribus labris gustassent genus hoc vitae, id. Cael. 12, 28: non a summis labris venire, not to be lightly spoken, Sen. Ep. 10, 3: similem habent labra lactucam, a saying of M. Crassus when he saw an ass eating thistles, and which may be rendered, like lips, like lettuce; meaning, like has met its like, Hier. Ep. 7, 5.
  2. II. Transf.
    1. A. An edge, margin, brim (of a vessel, a ditch, etc.): ut ejus fossae solum tantundem pateret, quantum summa labra distarent, Caes. B. G. 7, 72: extra duplex vallum fossae circumdedit, interiore labro murum objecit, Liv. 37, 37, 11: labra doliorum, Cato, R. R. 107, 1: fontis, Plin. 31, 2, 19, § 28: lilium resupinis per ambitum labris, id. 21, 5, 11, § 23; 17, 22, 35, § 168.
    2. * B. Poet., a trench, Aus. de Clar. Urb. 5, 9.
    3. C. Labrum Venerium, a plant growing by rivers, Plin. 25, 13, 108, § 171; called also labrum Veneris, Ser. Samm. 1038.