last changed in 2002
Morphology is the (study of the) internal morphological structure of words, in contrast with syntax, which is the (study of the) patterns in which words combine with each other. Another kind of internal structure for words is phonology, but morphology is the special kind of structure whose patterns are directly relevant to either syntax or semantics; e.g. in tacks the phonological structure is exactly the same as for tax, but their morphological structures are different - two morphemes as against one.
Morphology explains any difference between a word's stem and its complete form - its 'word-form' - and between its stem and any roots contained in the stem. E.g. in baby-sitters, the stem is baby-sit (the stem of the lexeme BABY-SIT), so morphology explains the presence of the affix -s and the presence of the two roots baby and sit inside the stem. Morphological generalisations are expressed in terms of morphological functions, e.g. the word-form of Plural is the s-form of its stem.
The two main branches of morphology are inflectional and derivational morphology, which deal with different uses to which morphological structures are put: distinguishing inflections and lexemes respectively. E.g. in baby-sitters, the affix -s is inflectional because it distinguishes the plural inflection, while -er is derivational, because it distinguishes the lexeme BABY-SITTER from BABY-SIT, and the combination of roots baby and sit is also handled by derivational morphology because it relates this lexeme to two simpler lexemes, BABY and SIT.
This is an article from the Encyclopedia of Word Grammar and English grammar. If you refer to it, please give the url as "http://tinyurl.com/wg-encyc".