This compact, presentable and best-selling dictionary is a fully up-to-date, comprehensive and clear compact dictionary that is the ideal reference aid for learners and speakers of Welsh. It contains over 20,000 headwords, and irregular forms of adjectives, verbs and plural nouns are included. In addition, there is an appendix of irregular Welsh verbs. Mae'r geiriadur gwerthiant uchel hwn yn glir, yn gryno, yn gyfoes ac yn gynhwysfawr. Mae'n ddelfrydol ar gyfer dysgwyr a Chymry Cymraeg. Ceir dros 20,000 o benawdau, yn cynnwys ffurfiau afreolaidd ansoddeiriau, berfau ac enwau lluosog ynghyd ag atodiad yn rhedeg y prif ferfau afreolaidd. D. Geraint Lewis is an award-winning author of numerous Welsh dictionaries and books of grammar. He has recently completed a Welsh Children's Thesaurus and is currently working on a collegiate dictionary for the Welsh Joint Education Committee. Other works include collections of Christmas Carols for children and a major volume of Folk songs. Prior to his retirement he was an Assistant Director of Education with responsibility for Cultural Services in the County of Ceredigion. Enillodd D. Geraint Lewis wobr Tir NaN'Og am Geiriadur Gomer i'r Ifanc.
Ers hynny y mae wedi cyhoeddi nifer o eiriaduron a llyfrau gramadeg. Mae wedi cyhoeddi Thesawrws Plant yn ddiweddar ac yn gweithio ar eiriadur 6ed dosbarth i Gyd-bwyllgor Addysg Cymru. Ymhlith ei weithiau eraill ceir cyfrolau o garolau Nadolig i blant a chyfrol gynhwysfawr o ganeuon traddodiadol, Can Di Bennill. Cyn ymddeol, bu'n Gyfarwyddwr Addysg Cynorthwyol yn gyfrifol am Wasanaethau Diwylliannol yng Ngheredigion.