In the Oradia Oracle, the Joy card belongs to the Emotions family. It carries a yang polarity, turned toward expansion and momentum rather than withdrawal. Drawing the Joy card generally signals a movement of lightness passing through the present moment, an energy that circulates without effort or calculation. It's a card that accompanies periods when something opens naturally, with no need to force it.
In Oradia's mirror-card system, Joy answers to Sadness: the two don't oppose each other, they answer each other, like two sides of the same movement.
This page gives the card's general meaning. In a real draw, the Joy card is always read in relation to the other cards drawn and the intention set at the start — it's that combined reading, unique to each draw, that the online oracle develops.