Difference between `advisor’ and `adviser’

There is no difference in meaning between the two words. Both are used to refer to someone (usually an expert) whose job it is to advise other people. For example, film stars often consult financial advisers to find out what to do with their money. When they get into trouble, the stars consult a legal adviser. Most dictionaries that we get in India, list `adviser’ as the first choice, and `advisor’ as the second. This is because in British English the word is spelt `a..d..v..i..s..e..r’; `a..d..v..i..s..o..r’ is the way Americans spell the word. While surfing the net, one encounters `advisor’ much more frequently than `adviser’

Source: ‘Know Your English’ (The Hindu) – August 07, 2006