My disclaimer is that I'm much more familiar with the old fashioned way of getting across the galaxy while in cryosleep, and I've only heard about this second-hand. But I'm going with something else. It's called L-space, and apparently the geometry is wrong and makes most people feel spacesick, but some lucky people can cope with it and become astrogators. The distances between places are much shorter in L-space than in our regular three dimensions, so I think 'wormhole' is a fair description, even if the guy who invented it might disagree.