Yaw is the side-to-side rotation or swerving motion of a boat around its vertical (Z-axis), causing the bow to swing left and right off its intended course. Often caused by waves, wind, or improper steering, it represents an angular deviation from the straight-line heading.

Key Aspects of Yaw in Sailing:
Motion: A horizontal, twisting, or "swiveling" movement, similar to turning a chair side-to-side.

Causes: Usually initiated by waves striking the stern or bow, or by uneven force on the rudder.

Result: The vessel momentarily deviates from its set course, which can cause discomfort or seasickness.

Context: While primarily a nautical term for a ship's unintentional movement, it is also used in aviation to describe rotation about the vertical axis.

Yaw is often discussed alongside other vessel motions, specifically pitch (up and down) and roll (tilting).