The kanji 洪 primarily conveys the meaning of "flood," "vast," or "great." It often describes something that is abundant, overflowing, or immense like a large body of water.

・On-yomi (音読み): コウ (kō) ・Kun-yomi (訓読み): None, or used rarely.

⚫︎洪水 (こうずい) Translation: Flood ⚫︎洪大 (こうだい) Translation: Vast; immense; great ⚫︎洪水の被害 (こうずいのひがい) Translation: Flood damage

The kanji 洪 is a 形声文字 (keisei moji), a phono-semantic compound. It combines two components: the radical 氵 (さんずい, "sanzui"), which represents water, and the phonetic component 共 (きょう, "kyō"). The component 共 suggests the sound and contributes the meaning related to the sound of 洪. The presence of the water radical (氵) clearly indicates the connection with water, specifically in a large quantity or overflow.