Close observation and comparison of words clearly shows that a great many words have a composite nature and are made up of smaller units, each possessing sound-form and meaning. These are generally referred to as morphemes defined as the smallest indivisible two-facet language units. Like a word a morpheme is a two-facet language unit, an association of a certain meaning with a certain sound-pattern. Unlike a word a morpheme is not an autonomous unit and can occur in speech only as a constituent part of the word.