When checking the info of a Monster, there are three numeric stats beside a thumbnail image of the Monster: HP, ATK, and RCV (or RCU). I was told that RCV refers to "received damage", implying that the higher the number, the more prone the Monster is to taking damage or the more damage the Monster takes. I speculate that it is a defense stat with an opposite indication: the higher the number, the less damage is received. Are either of these beliefs correct?
RCV is actually short for "recovery" and relates to how much healing you'll get from matching hearts together. From my guide:
Just below your team is your HP bar. As enemies attack, they’ll deplete this, and you can restore it with your team’s Recovery (RCV) stat by matching the heart orbs together.
Or the PAD Wikia:
RCV: The base amount of HP you will recover by matching 3 Heart Orbs in battle. This value is the RCV sum of all the monsters on your team, but the actual value in battle also adds the RCV of your friend's leader.