Lewis & Short

1. aethra, ae, f., = αἴθρα [v. aestas],

  1. I. the upper, pure air, the bright, clear, serene sky: aetheris splendor, qui sereno caelo conspicitur, Serv. ad Verg. A. 3, 585 (poet.): flammea, Jul. ap. Macr. 6, 4 (Trag. Rel. p. 228 Rib.): siderea, Verg. A. 3, 585.
  2. II. Transf., like aether, the sky, air, heavens: surgere in aethram, Lucr. 6, 467: volans rubrā ales in aethrā, Verg. A. 12, 247; so Sil. 4, 103; Stat. S. 1, 2, 135 al. (but in Cic. N. D. 2, 15, 42, the correct read. is aethere, B. and K.).

2. Aethra, ae, f., = Αἴθρα.

  1. I. Daughter of Oceanus and Tethys, mother of Hyas (in Hyg. Fab. 192 called Pleione), Ov. F. 5, 171.
  2. II. Daughter of Piltheus and mother of Theseus, acc. to Ov. H. 10, 131, and Hyg. Fab. 37.