1. Noun, Noun which may take the genitive case particle 'no'

   blue; azure

   信号が青に変わったわよ。

2. green

   mostly in compound words and in ref. to fruits, plants and traffic lights

3. Noun

   green light (traffic)

   Abbreviationsee 青信号

4. black (horse coat color)

   see 青毛

5. blue 5-point card

   HanafudaAbbreviationsee 青タン

6. Prefix

   immature; unripe; young

Also written 蒼【あお】ao、碧【あお】ao