What does this mean? right-sided transverse process of l5 is partially sacralized?

Transverse process: the transverse process is a small bone that comes off the side of the vertebrae for muscle to attach to. A sacralized tranverse process means that it is larger than normal and may be partially fused to the sacrum. This is rarely a cause for any pain or other symptoms. This is just an anatomic variation which is quite common.