However, the name is pronounced with the accent on the middle syllable (over the years, attempts by people to spell the name as they heard it have resulted in versions like Beck Armett in 1570, and Bekyremet in 1279).

In the 12th century there was an h in the middle, the earliest known version, from 1130, being Bechermet, so the English Place-Name Society suggests that the name really means "hermit's stream".

St Bridget included most of the small village of Calder Bridge, and the hamlet of High Sella field, along with about half of the nuclear plant.

The church of St. John, in the centre of the village, was rebuilt in 1878–79, but it too has fragments of ancient crosses, and many carved stone medieval coffin lids.

The outline of the later fortification, known as Caernarvon Castle, can still be traced in the fields north of the village (grid reference NY021073); it was abandoned about 1250 when the family moved to Coniston.

Although Caernarvon was identified as a castle site by a later member of the family, 17th century historian Sir Daniel Fleming, some experts believe it was never inhabited, and that its alternative name "Coneygarth Cop" may indicate that it was a medieval rabbit warren.