Pil (placename)

The name is defined as the tidal reach of a waterway, suitable as a harbour, and is common along the Bristol Channel and Severn Estuary.

The highly localised distribution suggests it may have been part of a common maritime culture on the waterways within the tidal reach of the Severn Sea.

It is thought that Pîl developed a secondary meaning of 'refuge', as the name also appears in more inland areas (such as Pilleth in Powys).

This is perhaps most evident on the River Usk, where Pîls were located both at the old Roman port of Caerleon and at the new Norman castle further south.

Nineteenth century Welsh writers would often define the term in line with William Owen Pughe's 1803 definition as "a small inlet of the sea filled by the tide".