sky / skī/ • n. (pl. skies) (often the sky) the region of the atmosphere and outer space seen from the earth: hundreds of stars shining in the sky| Jillson had never seen so much sky. ∎ poetic/lit. heaven; heavenly power: the just vengeance of incensed skies.• v. (skies, skied) [tr.] inf. hit (a ball) high into the air: he skied his tee shot. ∎ hang (a picture) very high on a wall, esp. in an exhibition.PHRASES: out of a clear blue skysee blue.the sky's the limit inf. there is practically no limit (to something such as a price that can be charged or the opportunities afforded to someone).to the skies very highly; enthusiastically: he wrote to his sister praising Lizzie to the skies.DERIVATIVES: sky·ey / ˈskīē/ adj.sky·less adj.
out of a clear blue sky without warning; unexpectedly (with reference to a ‘blue’ (i.e. clear) sky, from which nothing unusual is expected). Compare out of the blue.
sky-blue pink a non-existent colour; recorded from the mid 20th century.
the sky is falling a warning of imminent disaster, especially one which is regarded as unduly alarmist; the phrase comes from the nursery story in which Chicken Little and other animals repeatedly warn the king that the sky is falling down.
the sky is the limit there is practically no limit (to something such as a price that can be charged or the opportunities afforded to someone).
See also blue-sky, mackerel sky, pie in the sky, winter never rots in the sky.