OK I tried looking up a definition for you, but everything was too complicated .

Classical skiing is typically two parallel tracks and the motion is kind of like shuffling forward (it's really striding if you're doing it right, shuffling if you're me ), but the skis are pointed straight in front of you.

Skate skiing is a side motion with each leg - it mimics skating on ice skates. It's the side torsion that can mess with the knee - especially if your technique is off.

Does that help differentiate? Sorry to confuse the issue.

SheFly