The Picts dominated eastern and northern Scotland up to the 10th century. Although we know little about who the Picts were, we can guess from place name evidence that the now-extinct Pictish language was closely related to Brittonic languages such as Breton, Cornish and Welsh. Pictish settlements, for example, often had Brittonic prefixes such as Aber and Lan , as well as Pit -, a uniquely Pictish prefix indicating a portion or share of land. Aber is a common place name prefix in both Scotland [Aberdeen, Arbroath (Aberbrothick), Aberfeldy, Aberlour, Applecross (Aporcrosan)] and Wales [Aberdare, Abergavenny, Abertawe (Swansea), Aberystwyth]. Although it also occurs in Cornish and Breton, it is relatively rare. Aber means either the mouth of the river or its confluence with the sea and/or other rivers. It comes from an older Brittonic form ad-ber [ ad - , 'to, together’; beru- 'flow']. So Aberystwyth (on the west coast of Wales), for example, is at the
The Origins and Place Names of Brittany