Meaning
The bird of the divine realm; the celestial bird of the soul.
How Iqbal uses it
The tair-e-lahooti is the soul-bird that belongs to the world of the divine (lahut) and pines in the cage of the body; its yearning to break free and return to its true heaven is one of Iqbal's central images of the spirit's homesickness.
See it in the verse