ca.

Circa (often abbreviated c., ca., ca or cca. and sometimes italicized to show it is Latin) literally means "about" or "around". It is widely used in genealogy and historical writing, when the dates of events are approximately known.For example, an encyclopedia entry for Genghis Khan may begin with "Genghis Khan (circa 1162–August 18, 1227)".When used in date ranges, a circa is applied before each approximate date, while dates without a circa immediately preceding them are generally assumed to be known with certainty. For instance, the 1162 in the above example is approximate, but the August 18, 1227 is known.
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The Clandestine Insurgent Rebel Clown Army (or CIRCA or Smile LiberAtion Front) is a United Kingdom-based anti-authoritarian left-wing activist group that uses clowning and other non-violent actions to challenge corporate globalisation, war and similar actions that the group opposes.CIRCA emerged out of the direct action movement and has participated in protests against George W Bush's visit to the UK in 2003 and demonstrations against the 2003 invasion of Iraq. The group was particularly prominent in many of the actions organised around the 31st G8 summit held in Gleneagles during July 2005.
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circa, around, approximately

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