The crossword solution for the term COPPER, ONCE is CENT. Copper is a chemical element with the symbol Cu and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. Copper was one of the first metals to be used by humans, and it has been used for thousands of years in various forms. In its pure form, copper is a reddish-orange metal that has been used in coins, jewelry, and other decorative items since ancient times. The term 'copper, once' refers to the fact that copper was once used as a form of currency, specifically in the form of coins known as cents.