The Ghazal (pronounced "guzzle") is a poetic form that has both particular form, as well as standard themes.
Ghazals are composed of rhyming couplets (usually more than five and fewer than sixteen). Each line is the same length (although the metering is not conserved in English).
Each couplet ends with the same word or phrase (the refrain) and is preceded by the couplet's rhyming word (which appears twice in the first couplet).
The last couplet often includes a Proper Noun (i.e., the name of the poet).
Ghazals often express love, melancholy, longing and romance. Usually the gender of the lover is kept unspecified. More modern ghazals (especially those of Ghalib) cover much broader themes -- these include religion, politics and other social issues.
Ghazals are usually associated with Urdu poets. However ghazals were also written in Persian, Hindi and Hebrew. In modern times, Spanish and German authors have also experimented with the ghazal form.
The following is an excerpt from Agha Shahid Ali's Even in the Rain:
What will suffice for a true-love knot? Even the rain?
But he has bought grief’s lottery, bought even the rain.
“our glosses / wanting in this world” “Can you remember?”
Anyone! “when we thought / the poets taught” even the rain?
After we died—That was it!—God left us in the dark.
And as we forgot the dark, we forgot even the rain.