English Word-Formation (1983) by Laurie BauerAs you can see below, Bauer acknowledges the root/stem/

English Word-Formation (1983) by Laurie BauerAs you can see below, Bauer acknowledges the root/stem/base problem and then explains a model that removes the ambiguity.The Problem: “‘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. Of more recent years, however, there has been some attempt to distinguish consistently between these three terms.”Root: “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… In the form ‘untouchables’ the root is ‘touch’.”Stem: “A stem is of concern only when dealing with inflectional morphology. In the form ‘untouchables’ the stem is ‘untouchable’.” [In short, when you remove the inflectional suffixes, you have the stem.]Base: “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… ‘touchable’ can act as a base for prefixation to give ‘untouchable’.”@ladylinguist