In Cornish, it’s Nos Kalan Gwav, basically the same as the Welsh phrase, and means the “Night or Eve of the Calends of Winter”, Noevember 1st being Dy’ Halan Gwav. The Anglo-Cornish folklore name for the three-day period is Allantide, deriving from the ancient Celtic Saint, Saint Alan of Cornouaille (Kernev) in Brittany, although it’s tempting to see a possible connection between kalan/halan and Al(l)an too. Similar to the Welsh traditions, there were fires in some places in Cornwall and, certainly in West Cornwall, many traditions with red apples. In Brittany there is Kalan Goañv, and I think there might be a few old traditions with lanterns and apples there too. The modern, commercialised Hallowe’en, however, is so pervasive that it can be hard to discern what is “genuine” old folklore, and what is modern (re-)invention.