The industry uses Light as under 7,000kg, medium 7,000 - 136,000kg, and heavy as 136,000kg or more for wake turbulence.

At ~15 Metric Tons (33,000lb) take off weight it's a long way from a light aircraft. However, if your walking around these things, my personal view is a medium is around a Cessna Citation Mustang, double that and their large, and aircraft quickly get into huge and monsters.