A description that appeals to the senses (what is seen, heard, smelled, tasted or touched) and makes the reader perceive the scene, not merely understand it.
In Inferno
three times it made it spin with all the waters; at the fourth it raised the stern and sent the bow downward, as pleased the Other, until the sea closed over us.
The sea spins the ship three times, raises the stern and sinks the bow. The movement is described with precision, and the reader feels the fall of the boat up to the instant when the waters close.
see how I tear myself! See how Mahomet is mangled! Before me goes weeping Ali, with his face split from chin to crown.
already blind, groping over each one, and for two days I called them, after they were dead. Then, more than grief, fasting had power.
Cantos XXXI to XXXIV: The Ice and Lucifer, Ugolino, recounting how his children died in the tower
so that three winds were moving from him: from there all Cocytus was freezing. With six eyes he wept, and through three chins the tears dripped and the bloody slaver.
Cantos XXXI to XXXIV: The Ice and Lucifer, Dante, describing the wings and eyes of Lucifer
we ascended, he first and I second, until I saw through a round hole the beautiful things that heaven carries.
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