Geiriadur Gwybod y Geiriau (Dictionary for older Primary School Children - Key Stage 2) by D Geraint Lewis

This colourfully illustated hardback dictionary meets the requirements of the National Curriculum for Key Stage 2 children, aged 8-10, although the dictionary is mainly for older primary school children, secondary school children would also find it beneficial. 

With 1500 definitions including nouns, adjectives, verbs, phrases and useful tips to help you when writing, each letter of the alphabet has a different colour on the edge of the sheet.
This is an extremely useful dictionary, which is bilingually printed. 

An essential volume to use at school and at home.