ylä- + -stö, a loose translation of SwedishÖvitsböle (by interpreting its initial component as deriving from över-), which it is actually from an Old Swedish given name,[1] probably Övidh
The internal locative cases (inessive, illative and elative) are used with this place name when referring to a location; for example, "in Ylästö" is Ylästössä.
^ Timo Kallaluoto (2021) “Vantaan kaupunginosien nimet – osa 1”, in Andreas Koivisto, editor, 2021: Helsingin pitäjä – Vantaa. Vantaa-seuran vuosikirja., Vantaa-Seura – Vandasallskapet ry, pages 160–177