1. (noun) underground surface below which the ground is wholly saturated with water

• groundwater level
• water table

2. (noun) a line corresponding to the surface of the water when the vessel is afloat on an even keel; often painted on the hull of a ship

• water line
• waterline

1. (noun) the level of the surface of a body of water

• elevation

2. (noun) underground surface below which the ground is wholly saturated with water

• formation
• geological formation

3. (noun) a line corresponding to the surface of the water when the vessel is afloat on an even keel; often painted on the hull of a ship

• line

4. (noun) a water gauge that shows the level by showing the surface of the water in a trough or U-shaped tube

• water gage
• water gauge
• water glass

1. (noun) the level of the surface of a body of water

• sea level

2. (noun) a line corresponding to the surface of the water when the vessel is afloat on an even keel; often painted on the hull of a ship

• load line
• plimsoll
• plimsoll line
• plimsoll mark