Windsurfing: The wind flow actually felt by the windsurfer when on the water is a combination of the true wind, and the 'induced' wind created by the board's motion. (If sailing at 10mph, the induced wind will be 10mph onto the nose. The apparent wind is the wind actually experienced by the sailor (and rig!) and is a combination of the induced wind and the true wind. The faster you sail, the greater the induced wind, and thus the greater the apparent wind. The apparent wind also increases the closer you are sailing towards the true wind.