You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.

Category: SPORTING EVENTS 
Clue: The cup presented since 1887 to the man who wins this is inscribed "single handed champion of the world"
wimbledon

Category: ENGLISH 
Clue: Group of 4 letters that sounds different within words for done, exhaustive, hack, idea, branch & coarse
\"o-u-g-h\"

Category: REFERENCE BOOKS 
Clue: The name of this type of reference book comes from the Greek for "circle of instruction"

encyclopedia