Wavelength

(λ) the distance between two similar and consecutive points on a wave, which have exactly the same displacement value from the rest position (that is, the same amplitude). An example would be the distance between two crests (maximum displacement) or two troughs (maximum displacement). Wavelength is a measure of distance and hence has units of metres (m).

Taken from Dictionary of Science

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In physics, the wavelength of a sinusoidal wave is the spatial period of the wave – the distance over which the wave's shape repeats. It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a characteristic of both traveling waves and standing waves, as well as other spatial wave patterns. Wavelength is commonly designated by the Greek letter lambda (λ). The concept can also be applied to periodic waves of non-sinusoidal shape. The term wavelength is also sometimes applied to modulated waves, and to the sinusoidal envelopes of modulated waves or waves formed by interference of several sinusoids.

Assuming a sinusoidal wave moving at a fixed wave speed, wavelength is inversely proportional to frequency: waves with higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths.

Examples of wave-like phenomena are sound waves, light, and water waves. A sound wave is a periodic variation in air pressure, while in light and other electromagnetic radiation the strength of the electric and the magnetic field vary. Water waves are periodic variations in the height of a body of water. In a crystal lattice vibration, atomic positions vary periodically in both lattice position and time.

Wavelength is a measure of the distance between repetitions of a shape feature such as peaks, valleys, or zero-crossings, not a measure of how far any given particle moves. For example, in waves over deep water a particle in the water moves in a circle of the same diameter as the wave height, unrelated to wavelength.

Taken from Wikipedia

Parabola

a plane curve traced out by a point moving so that its distance from a fixed point (focus) is equal to its perpendicular distance from a fixed straight line (directrix). It is also the curve made by cutting a cone with a flat plane that is parallel to the side of the cone that slopes. Mirrors with a parabolic shape are used in searchlights and telescopes because incoming parallel rays of light are reflectd onto the focus. This property is used in a telescope, and thus the reverse applies in searchlights.

Taken from Dictionary of Science

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In mathematics, the parabola (pronounced /pəˈræbələ/, from the Greek παραβολή) is a conic section, the intersection of a right circular conical surface and a plane parallel to a generating straight line of that surface. Given a point (the focus) and a corresponding line (the directrix) on the plane, the locus of points in that plane that are equidistant from them is a parabola.

The parabola has many important applications, from automobile headlight reflectors to the design of ballistic missiles. They are frequently used in physics, engineering, and many other areas.

Taken from Wikipedia

Abscissa

the term given to the horizontal or x-co-ordinate when describing the position of a point on a graph. It is the distance of the point from the vertical or y-axis. For example, a point two units along the x-axis and three units up the y-axis is said to have CARTESIAN CO-ORDINATES (2,3) where the abscissa is 2.

Taken from Dictionary of Science

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In mathematics, abscissa (plural abscissae) refers to the first element of an ordered pair.

It is the first of the two terms (x, y) by which a point is referred to, in a system of fixed rectilinear coordinate (Cartesian coordinate) axes. The abscissa is also known as the "x" coordinate of a point. The second coordinate, or "y" coordinate, is called the ordinate.

Taken from Wikipedia

Radar

(radio detection and ranging) the use of radio waves to discover the presence and distance of an object. Radar is used in the navigation of aircraft, ships, missiles and satellites.

Taken from Dictionary of Science

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Radar is an object detection system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain. The term RADAR was coined in 1941 as an acronym for RAdio Detection And Ranging. The term has since entered the English language as a standard word, radar, losing the capitalization. Radar was originally called RDF (Radio Direction Finder, now used as a totally different device) in the United Kingdom, in order to preserve the secrecy of its ranging capability

Taken from Wikipedia