couplet:  two successive lines of verse forming a unit marked usually by rhythmic correspondence, rhyme, or the inclusion of a self-contained utterance

	Example:

Humpty Dumpty (nursery rhyme excerpt)

Humpty Dumpty sat on a wall
Humpty Dumpty had a great fall
 	
elegy:  a poem expressing sorrow or lamentation especially for one who is dead; a pensive or reflective poem that is usually nostalgic or melancholy

	Example:

In Memoriam A.H.H. (excerpt)
	
I hold it true, whate'er befall;
I feel it when I sorrow most;
'Tis better to have loved and lost
Than never to have loved at all.
—Alfred, Lord Tennyson, 1849

ode:  a lyric poem usually marked by exaltation of feeling and style, varying length of line, and complexity of stanza forms

Example:

Ode on a Grecian Urn (excerpt)

O Attic shape! Fair attitude! with brede 
Of marble men and maidens overwrought, 
With forest branches and the trodden weed; 
Thou, silent form, dost tease us out of thought 
As doth eternity: Cold Pastoral! 
When old age shall this generation waste, 
Thou shalt remain, in midst of other woe 
Than ours, a friend to man, to whom thou say'st, 
"Beauty is truth, truth beauty,"—that is all
Ye know on earth, and all ye need to know.
—John Keats, 1819 

(Source:  Definitions from www.merriam-webster.com)