noun, noun which may take the genitive case particle 'no'
lucky omen; good omen
Refers to a sign or event believed to foretell good fortune. Often used in formal or literary contexts, but also in everyday speech about auspicious signs.
初夢に富士山を見るのは吉兆とされている。
Seeing Mount Fuji in one's first dream of the year is considered a lucky omen.
虹
A rainbow is said to be a sign of good luck.