The term 'dude, colloquially' can be summed up by the crossword solution 'FELLA, ' which is a five-letter word. FELLA is an informal term used to refer to a man or boy, usually in a friendly or endearing way. It is derived from the Old English word 'feolaga, ' which means companion or associate. The term is often used in the United States and Canada, but it is also used in other English-speaking countries.