Welsh: of uncertain origin, probably connected with a Celtic word meaning ‘sea’. In the Mabinogi it is the name of the miraculously born son of Arianrhod, who became a minor divinity of the sea. Since the late 20th century the name has become popular outside Wales as a result of the fame of the Welsh poet Dylan Thomas (1914–53) and the American singer Bob Dylan (b. 1941), who changed his surname from Zimmerman as a tribute to the poet.
English: habitational name from any of the various places so called. The majority, with examples in at least fourteen counties, are named from Old English horh ‘mud’, ‘slime’ or horn ‘dirt’ + tūn ‘enclosure’, ‘settlement’. One in southern Gloucestershire, however, is named from Old English heorot ‘hart’ + dūn ‘hill’.