the horizontal plane or level corresponding to the surface of the sea at mean level between high and low tide.
the level of the surface of the sea with respect to the land, taken to be the mean level between high and low tide, and used as a standard base for measuring heights and depths
The level of the ocean’s surface. Sea level at a particular location changes regularly with the tides and irregularly due to conditions such as wind and currents. Other factors that contribute to such fluctuation include water temperature and salinity, air pressure, seasonal changes, the amount of stream runoff, and the amount of water that is stored as ice or snow. ◇ The reference point used as a standard for determining terrestrial and atmospheric elevation or ocean depths is called the mean sea level and is calculated as the average of hourly tide levels measured by mechanical tide gauges over extended periods of time.
- Sea-level pressure
[see-lev-uh l] /ˈsiˌlɛv əl/ noun 1. the atmospheric pressure, at any elevation, reduced by formula to a value approximating the pressure at sea level.
noun 1. a system for transporting persons or cargo by ship, especially in an emergency. 2. the act of transporting such persons or cargo. verb (used with object) 3. to transport (persons or cargo) by sealift.
noun 1. a stalked, sessile crinoid. noun 1. any of various sessile echinoderms, esp of the genus Ptilocrinus, in which the body consists of a long stalk attached to a hard surface and bearing a central disc with delicate radiating arms: class Crinoidea (crinoids)
noun 1. a resinous preparation, soft when heated, used for sealing letters, documents, etc. noun 1. a hard material made of shellac, turpentine, and pigment that softens when heated. It is used for sealing documents, parcels, letters, etc