commonality – (noun) something that others have too.
Examples:
The two organizations share a commonality of interests.
We mustn’t point an accusing finger to one group of young people, but use their commonality to bring them closer together.
When two negotiations partners discover their commonality, they will find it easier to sign an agreement.
The teachers at the school share a commonality of purpose in that they aim to teach the students valuable academic skills and knowledge while promoting independent thinking.