the.com/commonality
The shared thread that lets strangers nod at each other knowingly.
means A quality, feature, or interest that two or more things or people have in common.
from From Latin communis, shared or public, via Middle English commonalte, which once meant the common people before it meant common ground.
Old meaningOnce named the masses, not their shared traits
Math cousinUnderlies 'common factor' and 'common denominator'
Plural twistCommonalities are what icebreakers desperately hunt for