Flow
The smoothness with which a skater links speed, tricks and lines without it looking like effort.
Extended definition
Flow is one of the most valued things in skating and one of the hardest to fake. It's not doing hard tricks, it's chaining them keeping rhythm, speed and naturalness: a whole line looking like one thing, not four tricks stuck together. It goes hand in hand with carving, reading the terrain and personal style. Note: "flow" also means a low-tier sponsored rider (gets gear but no salary).