Let's describe wine
Dry is a widely used term, but around it there are a multiplicity of different experiences. In the first meaning that comes to mind, often negative, it is understood as the absence of water or humidity. Still, dry can also mean ironic, boring, arid, etc ... but this is not our case.
When we say that a wine is dry, we mean that it is without residual sugar. In simple terms, when we taste it we do not notice any sweetness (mainly with the front of the tongue) because all the sugar has turned into alcohol during fermentation.
So why not define it with the opposite of sweet, that is, bitter? Simply because bitter is not. Let's get rid of the idea - typical of coffe drinkers - that a not-sweet drink is necessarily bitter. The bitter is another sensation, not so appreciated in the world of wine, but that sometimes can give us pleasant moments together with the sweetness, for example tasting a passito wine.