Could have been a number of things.
ATC often make mistakes between left and right runways, circuits, etc., especially in high workload conditions. They often catch their own slip and correct right away, but sometimes you need to call them back and ask them to clarify their instruction. Which is exactly what you did (more strength to you), and the confirmed that they - in fact - wanted you to fly a right-hand pattern. Problem solved.
It could have meant they wanted you to fly a left-hand pattern. If there is only one (active) runway, controllers might send you on the other side in order to give everybody some room. But, again, they confirmed a right-hand pattern, so it probably wasn't that.
It could have meant "go to your left and join the downwind".
All in all, it doesn't matter at all what they meant. You did the right thing, which was to ask for clarification (or confirm the type of circuit) and you got it. Whenever ATC use terminology you don't understand or issue confusing instructions/clearances, always ask them to break it down for you before you do anything. Beyond that, it is of no real significance what they meant on that particular day. "Correct terminology" or not, controllers may express themselves in a number of ways and you can always ask them to explain what they want when it's unclear.