It indicates that the process is triggered when a signal is detected. This signal was broadcast communication from a business participant or another process.
The trigger is a signal transmitted by another process. Signals have only one ID and are not sent to a predefined destination (broadcast). The Signals can operate within a process (for example, between a subprocess and its parent process) or among processes of different participants.
The above picture provides an example where an "Accept Travel Voucher" signal triggers the start of a process. This will evaluate, and will accept or will reject the document for processing.
Objects: Business Process Diagram
None Start Event