Claim: A circle represents a set of operations or process while  an oval represents a terminal or the beginning and ending of a program.
Evidence: Open Vulnerability and Assessment Language (OVAL) is an international, information security, community standard to promote open and publicly available security content, and to standardize the transfer of this information across the entire spectrum of security tools and services. A circle is a shape consisting of all points in a plane that are a given distance from a given point, the centre; equivalently it is the curve traced out by a point that moves in a plane so that its distance from a given point is constant. The term "meeting" may refer to a lecture (one presentation), seminar (typically several presentations, small audience, one day), conference (mid-size, one or more days), congress (large, several days), exhibition or trade show (with manned stands being visited by passers-by), workshop (smaller, with active participants), training course, team-building session and kick-off event. A bulletin board system or BBS (also called Computer Bulletin Board Service, CBBS) is a computer server running software that allows users to connect to the system using a terminal program. A social grouping in Google+ Circle, a social networking service for iPhone and Android Circles was a core feature of the Google+ Social Platform.