Definition of Consonance:Similarity in consonant sounds in words that otherwise do not rhyme.
Example of Consonance #1:
Behind Me Dips Eternity, by Emily Dickinson
Behind Me -- dips Eternity --
Before Me -- Immortality --
Myself -- the Term between --
Death but the Drift of Eastern Gray,
Dissolving into Dawn away,
Before the West begin --
This poem contains consonance in the way it repeats the "t" sound, such as in "Eternity", "Immortality", "Term" & "Eastern". Two of the words rhyme, but most share only the common consonant sound, which is typical of consonance.
Example of Consonance #2:
The buzz-saw snarled and rattled in the yard
And made dust and dropped stove-length sticks of wood,
Sweet-scented stuff when the breeze drew across it.
And from there those that lifted eyes could count
Consonance appears in this poem in the way the "D" sound is repeated in "And made dust and dropped stove-length sticks of wood". Consonance often has an effect on the rhythm and meter of a poem.