Blue in Chinese / Japanese...

藍 is the single character for the color blue in Chinese.

It can also mean indigo in Japanese Kanji and old Korean Hanja.

蒼龍 is one of a couple possible titles for, "blue dragon" (occasionally also translated as "green dragon").

The first character means, "deep blue" or "azure."

The last character is dragon.

靑蓮 is a common title for Blue Lotus.

靑蓮 is often used in a Buddhist context for blue lotus from the Sanskrit "utpala." This often refers to the clarity and purity of the lotus blue eyes possessed by a Living Buddha. It can also represent purity of mind (without desire, suffering, fear etc).

蒼穹 is a poetic way to express "sky" in Chinese and Japanese Kanji.

It's like saying, "The blue dome of heaven," or a way to say "blue sky" within a poem.

青龍 / 靑龍 is a scholarly title for "Blue Dragon" or "Azure Dragon."

You'll find this title used in ancient Chinese literature and astronomy. This dragon has dominion over the eastern sky or eastern heavens. The Azure Dragon is also noted for representing the spring season. Also seen as an auspicious omen.

Emperor Huizong of the Song Dynasty canonized the five colored dragons as "kings." The Azure Dragon representing the most compassionate of kings.

In Japanese, this title is known with the same meaning but can also be a given name, Seiryuu.

Note, the first character can be written as OR . Same character, just two ways to write it.

青天 means clear sky, and/or blue sky in Chinese and Japanese Kanji.

Sometimes this term is used in Chinese to refer to an upright and honorable official or politician (a very rare thing).

In Japanese, this can also be the name Harutaka.

This title can mean blue or green dragon.

The first character can mean blue, green, azure, or celadon.

The second character means dragon.

This is mostly a Chinese title (especially in Buddhism). It will be understood but less commonly used in Japanese and Korean.