Lewis & Short

unguis, is (abl. ungui, Cat. 62, 43; Hor. Ep. 1, 19, 46; id. C. 2, 8, 4; Prop. 1, 20, 39; cf. Charis. p. 120), m. [cf. Gr. ΟΝΥΧ-, ὄνυξ; Sanscr. nakha], a nail of a person’s finger or toe.

  1. I. Lit., Plin. 11, 45, 101, § 247; 10, 35, 52, § 106; 28, 2, 5, § 28; Hor. Ep. 1, 7, 51; 1, 19, 46; id. S. 1, 3, 101; Prop. 1, 20, 39; Ov. Am. 1, 7, 64; 2, 6, 4; id. A. A. 3, 708.
      1. 2. Of animals. a claw, talon, hoof, Plin. 11, 45, 101, § 247; Hor. C. 2, 19, 24; Ov. M. 4, 717; 10, 540; Col. 6, 12; Mart. 14, 199 al.
    1. B. Proverbial phrases.
      1. 1. Ab imis unguibus usque ad verticem summum, from top to toe, from the crown of his head to the sole of his foot, Cic. Rosc. Com. 7, 20.
      2. 2. A rectā conscientiā transversum unguem non discedere, not to depart a finger’s breadth in the least, Cic. Att. 13, 20, 4; cf. ellipt.: urge igitur, nec transversum unguem, quod aiunt, a stilo, id. Fam. 7, 25, 2: si tu ex isto loco digitum transvorsum aut unguem latum excesseris, Plaut. Aul. 1, 1, 17 sq.; Hier. Ep. 127, 8 (v. transversus and digitus).
      3. 3. Cum medium ostenderet unguem, i. e. showed utter derision, the greatest contempt (because the middle finger was regarded as indecent), Juv. 10, 53.
      4. 4. Incestos amores De tenero meditatur ungui, i. e. from childhood, ἐξ ἁπαλῶν ὸνύχων, Hor. C. 3, 6, 24 (for which: a teneris unguiculis, Cic. Fam. 1, 6, 2).
      5. 5. Ad or in unguem, after the Gr. εἰς ὄνυχα or ἐπ’ ὄνυχος, to a hair, to a nicety, exactly, perfectly (an expression borrowed from sculptors, who, in modelling, give the finishing touch with the nail; or joiners, who test the accuracy of joints in wood by the nail: materiem dolare ad unguem, Col. 11, 2, 13: ad unguem Factus homo, highly polished, perfectly accomplished, Hor. S. 1, 5, 32; cf.: carmen decies castigare ad unguem, id. A. P. 294 Jan. ad loc.: suturae capitis in unguem committuntur, Cels. 8, 1, § 12; Verg. G. 2, 277 Serv.; Vitr. 4, 6, 2; cf. also: carmina molli numero fluere, ut per leve severos effundat junctura unguis, Pers. 1, 65.
      6. 6. Homo, cujus pluris erat unguis, quam tu totus es, a man whose little finger was worth more than your whole body, Petr. 57 fin.
      7. 7. Rodere ungues, to bite the nails, i. e. to be buried in thought, etc.: ille in versu faciendo Saepe caput scaberet vivos et roderet ungues, Hor. S. 1, 10, 71; cf.: ungue meam morso saepe querere fidem. Prop. 3 (4), 25, 4: et saepe inmeritos corrumpas dentibus ungues, id. 2, 4, 3 (13).
  2. II. Transf.
    1. A. Of plants, a nail-like spot, the tip, extremity, Plin. 12, 9, 19, § 36; 21, 18, 73, § 121; Col. 4, 24, 7; Pall. Febr. 12, 5.
    2. B. A kind of shell-fish, perh. the razor-fish, Varr. L. L. 5, 12, 23.
    3. C. A hook: ferrei, Col. 12, 18, 2.
    4. D. A white skin on the eye, a web, haw, πτερύγιον, Cels. 7, 7, 4.