The sensation of dryness in the back and under the edges of your mouth.  This is a desirable quality and not be confused with sour (which is considered a bad quality of coffee).  Acidity creates a lively, bright taste which without it, the coffee would taste flat.

Without aroma, we could only taste sweet, sour bitter and salty.  This is where we get the subtle differences such as floral, nutty or fruity.

The way the coffee feels in your mouth, its viscosity or heavinesss.  The best way to describe it is the comparison to how whole milk feels in your mouth compared to water.  If you are unsure as to the level of body in the different coffees, add an equal amount of mild to each one and the one with the heavier body will retain more of its flavor when diluted.  The Mexican coffee should have the lightest body and the Sumatran the heaviest, with the Yemen Mocha somewhere in the middle.

This is the overall perception of the three characteristics above.  Acidity has something to do with flavor, and so do body and aroma. Some coffees simply have a fuller, richer flavor than others, whereas other coffees have an acidy tang, for instance, that tends to dominate everything else.  Flavor can be rich (full bodied), complex (multi-flavored), or balanced (no one characteristic over powers the other).

Bright or dry - highly acidic leaving a dry aftertaste

Caramelly - caramel like or syrupy

Chocolaty - aftertaste similar to unsweetened chocolate or vanilla

Earthy - a soily-like quality (sometimes undesirable)

Fragrant - an aroma ranging from floral to nutty to spicy, etc

Fruity - having a citrus or berry scent

Mellow - a smooth taste lackin acidity but not flat

Nutty - similar to roasted nuts

Spicy - an exotic aroma of various spices

Sweet - a lack of harshness

Wild - a gamey flavor rarely, but sometimes considered favorable

Winy - aftertaste resembling a mature wine