Quite often, especially in science, I hear the term 'expert' used. Whether it be fashion expert, decorating expert, chemistry expert, bird flu expert, whatever it may be. So what is YOUR definition of 'expert'? What, in your opinion, qualifies a person to be an expert? Is the term used too loosely? Some people tell me "An expert is someone who knows EVERYTHING about their field of work". And other people might say other things. Just looking for some opinions, as it's something I've been thinking about.