Introduction to the Japanese Word Ao

Blue Sky
Ao could mean blue or green depending on the context. Getty Images

The Japanese word, ao, also known in Japanese characters as 青 (あお), means blue. There are other meanings depending on the context. 

Examples

Utsukushii aozora o aoide mita. - I looked up at the beautiful blue sky.
美しい青空を仰いで見た。

Watashi no ani wa aoi boushi o kabutte imasu - My brother wears a blue hat.
私の兄は青い帽子をかぶっています。

Ao could also mean "green." For example: aona 青菜 (greens), aoshingou 青信号 (green light).

When "ao" is put before certain words, it could mean "young" or "immature." Example: aokusai 青くさい (inexperienced), aonisai 青二才 (youth, novice).