grouping - the activity of putting things together in groups

indexing - the act of classifying and providing an index in order to make items easier to retrieve

reclassification - classifying something again (usually in a new category)

relegation - the act of assigning (someone or something) to a particular class or category

stratification - the act or process or arranging persons into classes or social strata

taxonomy - practice of classifying plants and animals according to their presumed natural relationships

typology - classification according to general type

arrangement - an orderly grouping (of things or persons) considered as a unit; the result of arranging; "a flower arrangement"

dichotomy, duality - being twofold; a classification into two opposed parts or subclasses; "the dichotomy between eastern and western culture"

basic cognitive process - cognitive processes involved in obtaining and storing knowledge

appraisal, assessment - the classification of someone or something with respect to its worth

ascription, attribution - assigning to a cause or source; "the attribution of lighting to an expression of God's wrath"; "he questioned the attribution of the painting to Picasso"

ascription, attribution - assigning some quality or character to a person or thing; "the attribution of language to birds"; "the ascription to me of honors I had not earned"

cross-classification, cross-division - classification according to more than one attribute at the same time; "the cross-classification of cases was done by age and sex"

subsumption - incorporating something under a more general category

restriction - the act of keeping something within specified bounds (by force if necessary)