Lewis & Short

jŭvĕnesco, nŭi, 3, v. inch. n. [juvenis].

  1. I. To reach the age of youth, to grow up (poet. and post-Aug.): vitulus … largis juvenescit herbis, Hor. C. 4, 2, 54: ex quo juvenuit, Tert. Exhort. ad Cast. 6 fin.
  2. II. To grow young again.
    1. A. Lit.: Pylius juvenescere posset, Ov. Am. 3, 7, 41: glires aestate juvenescunt, Plin. 8, 57, 82, § 224.
      Of plants: rosa recisa juvenescit, Plin. 21, 11, 40, § 69.
    2. B. Transf., to become vigorous, regain strength, flourish: gladii juvenescunt, Stat. Th. 3, 583: corpus regni juvenescit, recovers itself, Claud. Laud. Stil. 2, 20: continuo montes muro, id. VI. Cons. Honor. 534.