Description that appeals to the senses (what is seen, heard, smelled, tasted or touched) and makes the reader perceive the scene, not only understand it.
In the Aeneid
So far I could, sister Acca; now the bitter wound finishes me and everything around grows dark. Flee and carry this last order to Turnus: let him take up the fight and keep the Trojans away from the city.
“everything around grows dark” lets the reader see Camilla's sight fading. The image of darkness rising replaces any complaint and gives her death the composure of a commander who thinks only of the order.