Pen y Fan same noun "ban", in its plural form "bannau", is found in the Welsh name for the Brecon Beacons: "Bannau Brycheiniog". There is no one standard translation of "Pen y Fan", but 'the mountain's peak' or 'the beacon's summit' are both possible translations. Pen y Fan is formed from various units of the Old Red Sandstone which were laid down during the Devonian period. The lower slopes of the mountain are formed from the sandstones and mudstones of the Senni Formation whilst the upper slopes are formed from those of the Brownstones Formation. The very summit, like that of neighbouring Corn
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