This is the 10271st most frequent Japanese word.
青空
"青空" means "blue sky."
Here, 青空 refers to the physical sky that is free of clouds and appears blue. It's used in a literal sense.
今日は青空が広がっています。
Today, the blue sky is expanding.
In this sentence, 青空 is used metaphorically to describe something bright and cheerful, comparing the smile to the brightness of a clear blue sky.
彼女の笑顔は青空のように明るい。
Her smile is as bright as the blue sky.
青空 here is part of the term '青空市場,' which means 'open-air market,' implying outdoor spaces under the sky.