吉 (readings: きち, きつ, よし; Japanese kanji) means “Good Luck / Joy / Congratulations”. It is a Jōyō kanji taught in Japanese secondary school (junior & senior high) — the 高手 · Master tier beyond the grade 1–6 Kyōiku set, and appears in words such as 吉日 (lucky day).
What does 吉 mean?