A morpheme is the smallest linguistic part of a word that can have a meaning. In other words, it is the smallest meaningful part of a word. Examples of morphemes would be the parts "un-", "break", and "-able" in the word "unbreakable".
There are 5 types of morpheme:
- Free morpheme: a morpheme which can be joined with other morphemes (such as unbreakable) or on its own (such as break)
- Bound morpheme: a morpheme which can only be used when joined to other morphemes (such as unbreakable)
- Derivational morpheme: a morpheme which can be derived (added) to another morpheme to create a new word (such as adding -ness to happy to form the new word happiness)
- Inflectional morpheme: a morpheme which can change a word's tense, number, etc. (such as adding -s to dog to form the plural dogs)
- Allomorphs: different types of the same morpheme (for example, the morpheme ed can have the sound 'id' in the word hunted, the sound 't' in the word fished or the sound 'd' in the word buzzed)