The term 'underline' is used in a variety of contexts. In the context of a crossword puzzle, it can refer to a 10-letter word meaning to draw a line beneath something. An oceanographer is a 13-letter word referring to a scientist who studies the ocean and its inhabitants. Emphasize is a 9-letter word meaning to give special importance or emphasis to something. FEATURE is a 7-letter word meaning an important or distinguishing attribute or aspect of something. MARK is a 4-letter word meaning to make a visible impression or trace on something. ACCENTUATE is a 10-letter word meaning to emphasize or STRESS something. Finally, STRESS is a 6-letter word meaning to apply pressure or tension to something.