Esthwaite may mean either "the eastern clearing", with Middle Englishest, probably replacing Old Norseaustr 'east', and Norse þveit "clearing", or 'the clearing where ash trees grow', from Norse eski "ash trees, ash copse" (see askr) and again þveit.[2] Derivation from Brittonic*ïstwïth, "bent, curved, flexible, supple" has also been suggested (Welshystwyth, see River Ystwyth).[3]
The lake was mentioned as the location where William Wordsworth conversed with a friend in Wordsworth's poem, "Expostulation and Reply," part of Wordsworth's Lyrical Ballads and, in the same collection, it is the location for "Lines Left Upon A Seat In A Yew-Tree." Wordsworth also mentions it in his Prelude in line 267: "Make green peninsulas on Esthwaite's Lake", and also at line 570: "From Esthwaite's neighbouring lake the splitting ice".
The poem "The vale of Esthwaite" (1787) was Wordsworth's first effort at sustained composition.[5]
Ecology
Esthwaite is notable as one of the most nutrient rich of the mesotrophic lakes in Cumbria, with large seasonal and inter-annual variations in phosphorus supply.[6] As well as the more common British species of pondweed in the genus Potamogeton, slender naiad (Najas flexilis) is also present.[7]