Wynne, Hilary (2013) [2006]. "Theoden". In Drout, Michael D. C. (ed.). The J. R. R. Tolkien Encyclopedia (first ed.). Routledge. p. 643. ISBN 978-0-415-96942-0. 'the chief of a :þeod (a nation, people)'... His name as King, Theoden "Ednew," comes from the Old English ed-niowe, 'To recover, renew.'
