Circa. About the date cited. A term used in describing when a precise date of issue is not known for certain. In numismatics the date chosen should be considered within 25 years of its actual date (otherwise it would be expressed as the quarter century of a given century). See dates and dating.
excerpted with permission from
For Artists, Makers, Collectors and Curators
COMPILED AND WRITTEN BY D. WAYNE JOHNSON
Roger W. Burdette, Editor