Aldanna we have the BRB on the ipad, but it's no substitute for the CD version. We bought the BRB Deluxe (Dictionary and Thesaurus) in the app store, which cost about £7 and although it has all the words in it, there is no full text search. The search functionality is somewhat confusing, this review explains it better than I can...
"The main flaw is the search functionality, which is restricted to headwords and so misses over half the words in the dictionary. For example 'detective' comes under the headword 'detect', and while any type of search will return 'detect', none of them (wildcard, anagram, etc.) will return 'detective'. Similarly all the 'un-' words like 'undo' are hidden under headwords 'un- (1)' to 'un- (5)' and can't be searched. "
I believe the separate Dictionary and Thesaurus Apps have better reviews (£5 and £3 respectively)