line
Basic element of Euclidean geometry. Euclid defined a line as an interval between two points and claimed it could be extended indefinitely in either direction. Such an extension in both directions is now thought of as a line, while Euclid's original definition is considered a line segment. A ray is part of a line extending indefinitely from a point on the line in only one direction. In a coordinate system on a plane, a line can be represented by the linear equation ax + by + c = 0. This is often written in the slope-intercept form as y = mx + b, in which m is the slope and b is the value where the line crosses the y-axis. Because geometrical objects whose edges are line segments are completely understood, mathematicians frequently try to reduce more complex structures into simpler ones made up of connected line segments.
line
(1) A communications channel. See line card and port.
(2) In text-based systems, a row of characters.
(3) In graphics-based systems, a row of pixels.
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| The First Lines |
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| This photo, taken at Broadway and Cortlandt Streets in New York in 1883, shows a nation exploding with its first communications. The very same thing is happening today with the Internet, only the infrastructure is not visible. (Image courtesy of AT&T.) |
line1. Mathsa. any straight one-dimensional geometrical element whose identity is determined by two points. A line segment lies between any two points on a line
b. a set of points (x, y) that satisfies the equation y = mx + c, where m is the gradient and c is the intercept with the y-axis
2. American footballb. the players arranged in a row on either side of the line of scrimmage at the start of each play
3. a. the edge or contour of a shape, as in sculpture or architecture, or a mark on a painting, drawing, etc., defining or suggesting this
b. the sum or type of such contours or marks, characteristic of a style or design
4. a. a conducting wire, cable, or circuit for making connections between pieces of electrical apparatus, such as a cable for electric-power transmission, telecommunications, etc.
b. (as modifier): the line voltage
5. a route between two points on a railway
6. Chiefly Brita. a railway track, including the roadbed, sleepers, etc.
b. one of the rails of such a track
7. one kind of product or article
8. a unit of verse consisting of the number of feet appropriate to the metre being used and written or printed with the words in a single row
9. Physics a narrow band in an electromagnetic spectrum, resulting from a transition in an atom, ion, or molecule of a gas or plasma
10. Musica. any of the five horizontal marks that make up the stave
b. the musical part or melody notated on one such set
c. a discernible shape formed by sequences of notes or musical sounds
d. (in polyphonic music) a set of staves that are held together with a bracket or brace
11. a unit of magnetic flux equal to 1 maxwell
12. line ahead or line abreast a formation adopted by a naval unit for manoeuvring
13. the combatant forces of certain armies and navies, excluding supporting arms
14. Fencing one of four divisions of the target on a fencer's body, considered as areas to which specific attacks are made
15. the scent left by a fox
16. a. the equator (esp in the phrase crossing the line)
b. any circle or arc on the terrestrial or celestial sphere
17. above the linea. Bridge denoting bonus points, marked above the horizontal line on the score card
18. below the linea. Bridge denoting points scored towards game and rubber, marked below the horizontal line on the score card
line - 1. An electrical conductor. For distances larger
than a breadbox, a single line may consist of two electrical
conductors in twisted, parallel, or concentric arrangement
used to transport one logical signal.
By extension, a (usually physical) medium such as an optical fibre which carries a signal. | |