Y geiriadur mawr =
Subtitle: The complete Welsh-English, English-Welsh dictionary
By: H. MeurigEvans, W.O. Thomas ; golygydd ymgynghorol (consulting editor) Stephen J. Williams.
Contributors: Thomas, W. O.; Williams, Stephen J. 1896-
Edition: 7th ed.
Publisher: C. Davies
Published: 1976
Place of publication: Abertawe
Language: eng