Arabic nouns fall into a number of different categories depending on their morphology and their relationship to Arabic lexical roots. The extensive range of noun types yields a wealth of lexical possibilities that contribute to what Charles Ferguson has called the sense of “vastness and richness of the Arabic lexicon.” Two morphological criteria traditionally define Arabic nouns: they can take the definite article and/or they can take nunation.

Most Arabic nouns are derived from triliteral or quadriliteral lexical roots, and all nouns derived from a particular root are found in an Arabic or Arabic–English dictionary clustered under that root entry. Some nouns, however, have restricted roots; certain ones have only two root consonants, others have up to five root consonants. Yet other nouns have solid stems, unanalyzable into roots and patterns. This chapter is intended to give an overview of these noun types, with examples. It is by no means exhaustive and does not go into derivational detail within categories. For inflectional characteristics of nouns, see the chapter on noun inflection.

Arabic nouns are usually derived from lexical roots through application of particular morphological patterns. The use of patterns interlocking with root phonemes allows the formation of actual words or stems. Noun patterns themselves carry certain kinds of meaning, such as “place where action is done,” “doer of action,” “name of action,” or “instrument used to carry out action.” The most frequent MSA noun patterns are as follows.