Name of the room + number.
I'll give the human readable name a bit more info like if it's a fan (then it's 'Kitchen Fan 1', 'Kitchen Fan 2', etc...), but I'll usually make a group and expose the group to voice and the group would be based on the human name (Kitchen Fan). For most rooms though, I only really care about the room itself, so, "turn off the kitchen lights" is all that's really needed and that's handled by the zones.