1. The state of being that is commonly observed
   "The commonness of smartphones has changed how we communicate";
   - expectedness
    
2. The quality of lacking taste and refinement
   "The commonness of the decoration disappointed the art critics";
   - coarseness, grossness, vulgarity, vulgarism, raunch
    
3. Ordinariness as a consequence of being frequent and commonplace
   "The commonness of the design made it unremarkable";
   - commonplaceness, everydayness
    
4. Sharing of common attributes
   "The commonness of the cold virus makes it difficult to eradicate";
   - commonality

See also: common, uncommon

Type of: generality, inelegance, mundaneness, mundanity, normalcy [N. Amer], normality, ordinariness

Antonym: uncommonness