[If the text below uses any of the terms ‘hill-letter’, ‘river-letter’, ‘old-style name’, ‘transitional name’ and ‘inversion-type name’ a reader who is not familiar with those terms may wish to refer briefly to ‘The Celtic names of hillforts’, where an explanation of those terms is given].
The Celtic names of hillforts
OS map reference: NZ 283 417
Celtic name: Abisson
Source: Ravenna Cosmography (175) - Abisson
This is a promontory fort standing high above the river Wear at a point a little upstream from the centre of Durham, the drop down to the river being precipitous.
The writer’s reasons for associating the name Abisson with Durham are given in Chapter 15 (Roman place-names in the North of England) of the Home menu. The essa-type ending, when used in British names, appears to be applied to places at the top of a steep slope and overlooking a river. The part of the name before the ending comprises either the hill-letter s (as in Certisnassa) or the corresponding river-letter b (as in Duabsissis), though this b may be changed to v (as in Devionisso). In Celtic Abisson the first part of the name is just the river-letter b. This b later became the initial V of Vedra, the Romano-British name of the river Wear.
The Celtic name of the promontory fort was apparently transferred by the Romans to a fort which they built somewhere in the vicinity, most probably at a point where it could control a crossing of the river, though no trace of this fort has yet been found.