Consonance is a type of rhyme that occurs when two or more words have the same consonant sound, but different vowel sounds. For example, the words "dog" and "frog" have the same consonant sound, but different vowel sounds.
Alliteration is a type of rhyme that occurs when two or more words begin with the same consonant sound. For example, the words "Peter Piper picked a peck of pickled peppers" all begin with the consonant sound "p".