The kanji 虹 means "rainbow." It represents the colorful arc that appears in the sky after rain, caused by the refraction and reflection of sunlight in water droplets. This character directly relates to this natural phenomenon.

・On-yomi (音読み): こう (kō) ・Kun-yomi (訓読み): にじ (niji)

⚫︎ 虹が出ている Translation: A rainbow is out. ⚫︎ 虹を見た Translation: I saw a rainbow. ⚫︎ 虹色 Translation: Rainbow-colored

The kanji 虹 is a phono-semantic compound (形声文字, けいせいいもじ). The phonetic component is 工 (kō), which is used for its sound. The meaning component is 虫 (mushi), which originally meant "snake" or "worm." The character 虹, therefore, historically depicted a "sky snake," which was a poetic way to describe the rainbow, borrowing the phonetic component to signify the sound.