under the sky, in the open air, Pi. O. 6.61; ὑ. κατακοιμηθῆναι Hdt. 4.7, cf. Th. 1.134; of troops, Hdt. 7.119, X. An. 5.5.21, 7.6.24: also of things, λύχνα καίειν ὑπαίθρια Hdt. 2.62; τῶν ὑ. πάγων δρόσων τε A. Ag. 335; ὑπαιθριοις δεσμοῖς πεπασσαλευμένος Id. Pr. 113; ὑ. δρόσος E. l.c.; ὑ. δεξαμεναί, opp. ὑπόστεγοι, Pl. Criti. 117b; ἔστι . . ὑ. τὸ στιππύον ἐρριμμένον PSI 4.404.7 (iii B.C.); ὑ. ἔργα outdoor work, X. Oec. 7.20:—in the open, in public, ὑπαίθριος πεῖραν αὑτοῦ διδούς Luc. Apol. 14.
as Subst., ἐν ὑπαιθρίῳ, = ἐν ὑπαίθρῳ, Gal. 6.94, cf. Hdn. Epim. 140.