In sailing, lee (or leeward) refers to the side of a vessel sheltered from the wind, opposite to the windward side. It is the direction toward which the wind is blowing. The "lee side" is typically the lower side when a boat is heeling, while a "lee shore" is land downwind of a boat.
Understanding the leeward side is critical for:
Right of Way: In many sailing rules, the leeward vessel has the right of way over a windward vessel when they are on the same tack.
Safety: Sailors must constantly be aware of a lee shore to avoid being trapped against a coastline during a storm.
Shelter: When docking or anchoring, sailors often look for the lee of the land to find calmer waters protected from the wind.