Circa（经常缩写为c., ca., ca, cca.，有时用斜体以表明其为拉丁文），意为“大约”，其字面意思是“周围”，一般是指一个日期。
Approximately – should be used with qualifier P1480 to indicate the source specified a value and explicitly stated that value is approximate, but specify no precision information. For example, "born around 1709"