The Hamoaze (/hæmˈoʊz/; Cornish pronunciation: [ˈhɒmøz]) is an estuarine stretch of the tidal River Tamar, between its confluence with the River Lynher and Plymouth Sound, England. The name first appears as ryver of Hamose in 1588 and it originally most likely applied just to a creek of the estuary that led up to the manor of Ham, north of the present-day Devonport Dockyard. The name evidently later came to be used for the estuary's main channel. The ose element possibly derives from Old English wāse meaning 'mud' (as in 'ooze') – the creek consisting of mud-banks at low tide.