noun

a point or way in which people or things are dissimilar.

the differences between men and women

dissimilarity,contrast,distinction,distinctness,differentiation,variance,variation,variability,divergence,deviation,polarity,gulf,breach,gap,split,disparity,imbalance,unevenness,incongruity,contradiction,contradistinction,nonconformity,unlikeness,contrariety,dissimilitude

verb

alter (a coat of arms) to distinguish members or branches of a family.