sameness
     n 1: the quality of being alike; "sameness of purpose kept them
          together" [ant: {difference}]
     2: the quality of wearisome constancy and lack of variety; "he
        had never grown accustomed to the monotony of his work";
        "he hated the sameness of the food the college served"
        [syn: {monotony}]
Source: WordNet® 2.0