1. The quality of being synchronous; the occurrence of two or more events at the same time: The synchronism of the two concerts in the city was not expected and meant that they would take place simultaneously, meaning that it was difficult for people to choose which one to go to!
2. Arrangement or treatment of synchronous events, etc. together or in conjunction: Mr. Straight was responsible for the synchronism of the city's historical events and important persons by putting them into tabular lists to show similarities in the occurrences.
3. Representation of events of different times together, e.g. in the same picture: As an example of synchronism at the museum, Mary saw a big work of art showing various incidents and occurrences that happened at different times in history.

The simultaneous appearance of two separate events; synchronicity: The students seemed to be very happy with their teacher, and their teacher with them, so there was a good rapport of synchrony among them.