Lewis & Short

a-gnascor (adg-), nātus, 3, v. dep. [ad-gnascor, nascor].

      1. 1. To be born in addition to; commonly,
    1. A. Of children that are not born until after the father has made his will: constat agnascendo rumpi testamentum, Cic. de Or. 1, 57, 241; so id. Caecin. 25; Dig. 25, 3, 3.
      Metaph.,
    2. B. Of adopted children, to accrue by adoption: qui in adoptionem datur, his, quibus agnascitur, cognatus fit, Paul. Dig. 1, 7, 23; cf. id. ib. 1, 7, 10.
  1. II. Of plants, to grow to, at, or upon something: viscum in quercu adgnasci, Plin. 16, 44, 93, § 245; 27, 11, 73, § 97.
  2. III. Of teeth, to grow afterwards, Gell. 3, 10.
    Of hair, Plin. 11, 39, 94, § 231.
    Of limbs: membra animalibus adgnata inutilia sunt, Plin. 11, 52, 113, § 272.
    Of plants: tubera et cetera quae subito adgnascuntur, Scrib. Comp. 82.
    Hence, agnā-tus (adg-), a, um, P. a.
    1. A. Lit., born to, belonging to, or connected with by birth; and subst., a blood relation by the father’s side (father, son, grandson, etc.; brother, brother’s son, brother’s grandson, etc.; uncle, cousin, second cousin, etc.); accordingly of more limited signif. than cognatus, which includes blood relations on the mother’s side; the idea in gentilis is still more extended, including all the persons belonging to a gens, and bearing the same gentile name, e. g. the Cornelii, Fabii, Aemilii, etc., v. Smith’s Dict. Antiq.; Gai Inst. 1, 156; Ulp. 26, 1, 10, § 2; cf. Zimmern, Röm. Priv. Rechtsgesch. 1, 507 sq.
      Even the XII. Tables mention the Agnati: SI. (PATERFAMILIAS) INTESTATO. MORITVR. CVI. SVVS. HERES. NEC. SIT. ADGNATVS. PROXIMVS. FAMILIAM. HABETO., Cic. Inv. 2, 50, and Ulp. Fragm. Tit. 26, § 1: SI. ADGNATVS. NEC. ESCIT. (sit) GENTILIS. FAMILIAM. NANCITOR., Mos. et Rom. Leg. Coll. Tit. 16, § 4: SI. FVRIOSVS. EST. ADGNATORVM. GENTILIVMQVE. IN. EO. PECVNIAQVE. EIVS. POTESTAS. ESTO., Cic. Inv. 2, 5; Auct. ad Her. 1, 13.
      Hence, the proverb: ad adgnatos et gentiles est deducendus, for a madman or insane person, Varr. R. R. 1, 2, 8.
    2. B. Ag-nāti, orum, subst., children born after the father has made his will (cf. I. A.): numerum liberorum finire aut quemquam ex adgnatis necare flagitium habetur, Tac. G. 19; id. H. 5, 5.