Morphology: ‘Root’, ‘Stem’ and ‘Base’

Taken from: Bauer, L. (1983) . English word-formation. Cambridge: Cambridge University Press.

‘Root’, ‘stem’ and ‘base’ are all terms used in the literature to designate that part of a word that remains when all affixes have been removed.

A root is a form which is not further analysable, either in terms of derivational or inflectional morphology. It is that part of word-form that remains when all inflectional and derivational affixes have been removed. A root is the basic part always present in a lexeme. In the form ‘untouchables’ the root is ‘touch’, to which first the suffix ‘-able’, then the prefix ‘un-‘ and finally the suffix ‘-s’ have been added. In a compound word like ‘wheelchair’ there are two roots, ‘wheel’ and ‘chair’.

A stem is of concern only when dealing with inflectional morphology.
In the form ‘untouchables’ the stem is ‘untouchable’, although in the form ‘touched’ the stem is ‘touch’; in the form ‘wheelchairs’ the stem is ‘wheelchair’, even though the stem contains two roots.

A base is any form to which affixes of any kind can be added. This means that any root or any stem can be termed a base, but the set of bases is not exhausted by the union of the set of roots and the set of stems: a derivationally analysable form to which derivational affixes are added can only be referred to as a base. That is, ‘touchable’ can act as a base for prefixation to give ‘untouchable’, but in this process ‘touchable’ could not be referred to as a root because it is analysable in terms of derivational morphology, nor as a stem since it is not the adding of inflectional affixes which is in question.