Collins Primary Dictionaries Collins Primary Thesaurus is a clear, practical thesaurus that builds writing and vocabulary skills. Colour headwords, an A-Z on every page and a full index make it easy to find the right word. Examples for every synonym (similar word) give you all the information you need to use words correctly. Essential word lists, antonyms, usage tips and help with pronunciation and writing build language skills even more. For ages 8+.