ADJ. big, huge | open We slept under the open sky. | empty | bright, clear, cloudless, sunny a week of cloudless skies | cloudy, dull, overcast, sullen | starry | azure, black, blue, dark/darkening, grey, pale, leaden | night, morning, etc. | autumn, January, etc. | northern, southern, etc.
QUANT. patch a patch of blue sky
VERB + SKY light up The fireworks lit up the sky. | patrol
SKY + VERB clear (up), lighten The rain stopped and the skies cleared. | cloud over, darken, turn grey, etc. | be streaked with sth The sky was streaked with gold.
PREP. across the ~ Black clouds spread across the sky. | against the ~ The eagle was black against the early morning sky. | beneath/under a ~ a ship tossing under a darkening sky | from/out of the ~ A strange object dropped out of the sky. | in the ~ There was a kite high up in the sky. | ~ above A helicopter appeared in the sky above them. | ~ over patrolling the skies over the Channel
PHRASES high/low in the sky when the sun is low in the sky | the sky above/overhead Swallows darted about in the sky overhead. | take to the skies (= to go into the sky) Some vintage aircraft will be taking to the skies at this weekend's fair.