To bloom or blossom (intransitive): when flowers open; can be used metaphorically (e.g., a smile 'blooms').
庭のチューリップがきれいに咲いた。
The tulips in the garden have bloomed beautifully.
春になると公園の桜が一斉に咲く。
In spring, the park's cherry trees all bloom at once.
彼女の笑顔が咲いた瞬間、場の空気が和らいだ。
When her smile blossomed, the atmosphere softened.
花は朝に咲いて夕方には萎む種類もある。
Some flowers open in the morning and wilt by evening.
Archaic/poetic: used to describe waves rising or breaking (e.g., white surf); now mainly literary.
古い和歌では、波が岩に当たって『咲く』と詠われることがある。
In old waka poems, waves hitting rocks are sometimes described as 'blooming'.