An area of sky with a formation of rounded and isolated cirrocumulus or altocumulus resembling the pattern of scales on the back of a mackerel.

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A representation, usually on a plane surface, of all or part of the surface of the earth, celestial sphere, or other area; showing relative size and position, according to a given projection, of the features represented. Such a representation intended primarily for navigational use is called a chart. A planimetric map indicates only the horizontal positions of features; a topographic map both horizontal and vertical positions. The pattern on the underside of extensive cloud areas, created by the varying amounts of light reflected from the earth’s surface, is called a sky map. A chart which shows the distribution of meteorological conditions over an area at a given moment may be called a weather map.


A flat coastal area flooded by most high tides, characterized by various species of marsh grasses and animal life.


A sailing tactic for handling winds too strong for the sail area hoisted when reefing the sails is not feasible or possible. The headsail is set normally while the mainsail is let out till it is constantly luffing. This creates loss of force on the main and also reduces the efficiency of the headsail while still retaining sailing control of the vessel.


  1. The major area of salt water covering the greater part of the earth. 2. One of the major divisions of the expanse of salt water covering the earth.


(1) The smallest area containing all possible survivor or search object locations. (2) For a scenario, the possibility area is the smallest area containing all possible survivor or search object locations that are consistent with the facts and assumptions used to form the scenario.


The general name for instruments used in air pollution studies for determining the amount of material deposited on a given area during a given time.


An area of pack ice less than 5.4 nautical miles (l0 kilometers) across.


In mapping, charting, and geodesy, the inconsistent application of algebraic sign to geographical references and the angular reference of azimuthal systems is a potential trouble area in scientific data collection. The following conventions have wide use in the standardization of scientific notation


Any lobe of the radiation pattern of a directional antenna other than the main or lobe.


one mast, two sails. The mainsail is aft of the mast and a jib forward of the mast, usually attached to the forestay. Spritsail rig - a sprit is a boom that extends upward from the mast foot to the topmost corner of a quadrangle sail. The rig extends the sail area set from a short mast.

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