Heterogeneity

n. quality of being made up of parts which are different from each other; incongruousness

Heterogeneous (American English)) means that something (an object or system) consists of a diverse range of different items. It is the antonym of , which means that an object or system consists of many identical items. Matters of a quantum can exist in homogenous or in heterogeneous or in combined distributions. The term is often used in a scientific (such as a kind of catalyst), mathematical, sociological or statistical context.
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Noun
1. the quality of being diverse and not comparable in kind
(synonym) heterogeneousness
(antonym) homogeneity, homogeneousness
(hypernym) nonuniformity
(hyponym) diverseness, diversity, multifariousness, variety

(n.)
The state of being heterogeneous; contrariety.
  

see Variability.