Use 'simultaneity' when emphasizing that events are aligned in time, often unexpectedly. She marveled at the simultaneity of falling stars lighting up the night sky.
Pro Tip 2/3
Unexpected Overlap
'Simultaneity' can suggest surprise when two events occur together without planning. Witnessing the simultaneity of two rare bird species appearing at once was extraordinary.
Pro Tip 3/3
No Causation
Remember that 'simultaneity' does not imply one event causes the other; it's just timing. The simultaneity of the alarm and the blackout was just coincidental.