Elegy :]

Definition: a mournful and thoughtful poem, a poem dealing with things of loss, of death, and sad things

Significance: express sorrow for someone who has died

Example:

Elegy Written in a Country Churchyard
by
Thomas Gray

The curfew tolls the knell of parting day,
The lowing herd winds slowly o'er the lea,
The ploughman homeward plods his weary way,
And leaves the world to darkness and to me.