waterline

Everyday

1. The line along the side of a ship or boat where the water reaches. tree →
2. A line or mark showing how high water has come, for example on a wall after a flood, or on a beach. tree →

In the lessons

In science lessons on floating, the waterline shows how deep a boat sits in the water: the more weight it carries, the lower it floats and the higher the waterline climbs up its side. After floods, waterlines on buildings show how deep the flood was. Phrases: "below the waterline", "above the waterline".

Examples

• The ship was painted red below the waterline. tree →
• When we added marbles to our foil boat, the waterline rose up its side. tree →
• A hole below the waterline can sink a ship. tree →
• You can still see the waterline on the walls from last year's flood. tree →
• The heavier the cargo, the lower the ship sits in the water. tree →
• We marked the waterline on our model boat with a pen. tree →

Note

Countable; usually "the waterline". One word (sometimes "water line"). Ships have special marks (Plimsoll lines) to show the safe waterline when loaded.