Jōyō kanji, Taught in junior high
JLPT level: N1
1778 of 2500 most used kanji in newspapers
Stroke count: 9
Meaning: deluge, flood, vast
Kunyomi:
Onyomi: コウ
Composition: 氵 共
Radical: 水
Meaning: water
洪 （コウ） Hungary
洪水 （コウズイ） flood, flooding