Book excerpt: Many of us don't know what a homonym is, yet we use them every day. The Wordsworth Dictionary of Homonyms, the first of its type published in Britain, will bring enlightenment. Do you get confused between 'to', 'too' and 'two'? Do you need to know the five definitions of 'fluke'? If so, then this is the book for you. A boon for crossword addicts, a treasure trove for punsters and an endless source of fascination for anyone interested in the English language.