Corn Du the last ice age by ice scouring out hollows below the peaks, the water being partly dammed by moraines of rock debris carried down by ice action subsequent to plucking and frost shattering. Corn Du Corn Du is a mountain immediately to the southwest of Pen y Fan and the second highest peak in South Wales at 873 m (2,864 ft), situated in the Brecon Beacons National Park. The summit itself is marked by a well structured Bronze Age cairn with a central burial cist like that on nearby Pen y Fan. The two summits are visible from great distances
Pen-y-ghent language, exactly as in today's Welsh, "Pen" meant 'top' or 'head', and "y" is most likely the definite article ("the"), exactly as in Modern Welsh "y". These elements are common in placenames throughout the island, and especially in Wales (compare Penyberth 'end of the hedge/copse', or Penyffordd 'head of the road/way', etc.). The element "ghent" is more obscure, however: it could be taken to be 'edge' or 'border'. The name "Pen-y-ghent" could therefore mean 'Hill on the border' (compare Kent). Alternatively, "ghent" could mean 'wind' or 'winds' – from the closest Welsh transliteration, "gwynt" ('wind'). Thus it might mean simply