The noun has 4 meanings:
Meaning #1:
the state of being that is commonly observed
Synonym: expectedness
Meaning #2:
the quality of lacking taste and refinement
Synonyms: coarseness, grossness, vulgarity, vulgarism
Meaning #3:
ordinariness as a consequence of being frequent and commonplace
Synonyms: commonplaceness, everydayness
Antonym: uncommonness (meaning #1)
Meaning #4:
sharing of common attributes
Synonym: commonality
