watercock Syllabification: (wa·ter·cock)Pronunciation: /ˈwôtərˌkäk, ˈwä-/Definition of watercock noun a brown and gray aquatic Asian rail, the male of which develops black plumage and a red frontal shield in the breeding season. Gallicrex cinerea, family Rallidae watercock in other Oxford dictionaries Definition of watercock in the British & World English dictionary