Phonosemantic compound. ⻏ represents the meaning and 者 represents the sound. Based on the meaning "large city, capital", which is the meaning when pronounced "dū". When pronounced "dōu", it has the unrelated meaning "all", etymologically related to 多 (many).
Chengdu subprovincial city and capital of Sichuan province 四川 in southwest China
Sound component in 1 character