Rhymes are the words usually placed in the end of the line of the verse that repeat its final sound under some systematic arrangement. This arrangement of rhymes is called rhyme scheme.
Sometimes rhymes are built within the lines and sometimes the rhymes within carry repeated sounds not on the final parts of words but in the beginning of them. All kinds of these rhymes give rise to rhythm and melody within the lines.
Sometimes the rhymes are not complete and perfect. They can be said as imperfect rhyme, incomplete rhyme, one eyed rhyme or half rhyme