Is it ensure, insure, or assure?
1765, "pertaining to historical coins and coinage," from French numismatique (late 16c.), from Latin numismat-, stem of numisma "coin, currency," from Greek nomisma "current coin, money, usage," literally "what has been sanctioned by custom or usage," from nomizein "have in use, adopt a custom," from nomos "custom, law, usage," from PIE root *nem- "to divide, distribute, allot" (see nemesis). Related: Numismatical (1716). Earlier in the same sense was nummary (1650s), from Latin nummarius, from nummus "a coin."