“sky / heaven” in Japanese is 天, read ten, ame, ama (てん, あめ, あま). It is a Grade 1 Kyōiku kanji, taught in year 1 of Japanese elementary school, and appears in words such as 天気 (weather).
What does 天 mean?
天気がいい。
Same sound, different character — the classic trap. Compare them side by side: