1. happening by chance at the same time or in the same way; not planned or intentional

Examples

• It was purely coincidental that we both wore the same dress to the party.
• The timing of his arrival was coincidental – he didn’t know about the meeting.
• Their similar ideas were coincidental since they worked independently.
• The power outage was coincidental with the storm, not caused by it.
• Meeting my old teacher at the airport was completely coincidental.
• The coincidental discovery of the document changed everything.