Alun \a-lun\ as a boy's name is of Welsh origin. An ancient Welsh name, indirectly related to Alan, of which it is now generally taken to be the Welsh equivalent. It is borne by the character Alun of Dyfed in the "Mabinogi". It is also the name of a river and a regional name in Wales, sometimes called Alyn. Alun became popular after it was used as a bardic name by John Blackwell (19th century).