Morphology comes from a Greek word meaning shape or form and refers to the study of words and how they are formed. It examines both the internal structure of words and how they combine to form larger linguistic units. There are two types of morphemes - free morphemes which can stand alone like "tree" and bound morphemes which need to be attached to other morphemes like "-s". Bound morphemes include prefixes, suffixes, and infixes. Inflectional affixes are bound morphemes that carry grammatical meaning and create new forms, while derivational affixes form new words.