Ling/Engl 215 is about the systematic study of words in English. Such systematic study relies on a body of knowledge and concepts that are well established in the field of Linguistics. Although the course is not designed to teach the field of Linguistics, we need to rely on the terminology and associated concepts established in Linguistics to a certain extent, especially in the parts of the course dealing with word structure and analysis.
The definitions below are designed to help with the acquisition of the concepts that the course introduces.
A meaningful element in a word that cannot be broken down further into meaningful subparts. Morphemes are thus minimal units of meaning in a word. They are units that link a form, which is a distinctive string of sounds, with a meaning or a function.
A morpheme is uniquely identified by its form and meaning together, e.g. bi 'two', or pol 'community, city', or bi 'life'. Two different morphemes can have the same form, or two morphemes can happen to have the same meaning. So similarity or identity of form does not mean that two items are the same morpheme, nor does similarity or identity (if meanings can ever be identical) of meaning indicate that two items are the same morpheme.