In describing inflected languages, like Latin, Greek, or Sanskrit, a distinction between affixes (pre-, in-, and suffixes) and desinences (grammatical endings) is usually made. The former are usually called derivational morphemes (they change the meaning), and the latter inflectional (they indicate the syntactic relationships between words in a phrase). In the study of morphology, there is a difference between free and bound morphemes: free ones can stand on their own, but bound ones are usually affixes, though some like the
rasp in
raspberry are not. The problem may be with less inflected languages, like English or Chinese. There a lexeme (aka lexical item, word) like
man consists of a single morpheme, though come to think of it the Latin nominative singular
vir 'man' has no explicit nominitival desinence, as
rosa (i.e., the -
a) does). Distinguishing between roots (single morphemes) and bases (root morpheme plus one or more affixes, or compounds) seems like a goodly distinction, though perhaps overkill for English morphology.
[Addendum: More on
roots and
stems.]
