The crossword solution for the term 'Heavy Marble' is 'Steelie', which is a seven-letter word. Steelie is a type of marble game that involves using steel marbles to knock other marbles out of a circle. It is a popular game among children and adults alike, and is often played in parks or on sidewalks. The game requires skill and strategy, as players must use their steel marbles to knock other marbles out of the circle without getting their own marbles knocked out.