This is the newest category of yarns! Recently, we've had some super large gauge yarns enter the market and their difference warranted a new name to differentiate them from the super bulky lines. Jumbo yarns are also sometimes called "roving".
Knit Gauge (stockinette): 6 sts and fewer/10cm on 12.75mm and larger knitting needles
Crochet Gauge (single crochet): 6 sts and fewer/10 cm on 15.0mm and larger crochet hooks
For more information about yarn gauges and classifications, visit the Craft Yarn Council website.