magnet

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. An object that is surrounded by a magnetic field and that has the property, either natural or induced, of attracting iron or steel.
2. n. An electromagnet.
3. n. A person, a place, an object, or a situation that exerts attraction.

Century Dictionary and Cyclopedia

1. n. A body which possesses the property of attracting fragments of iron or steel, and which, when freely suspended, tends, under the action of the earth, to take a certain definite position, pointing approximately north and south. The lodestone, a variety of the mineral magnetite, or the native magnetic oxid of iron (Fe₃0₄), is a natural magnet; but the properties of the magnet are best shown by an artificial magnet (see below), which has commonly the form of a straight bar or that of a horseshoe. When a bar-magnet is dipped into iron-filings. it is found that they adhere most strongly at the extremities of the bar (which are called the poles of the magnet), and not at all along the line midway between them. Strictly speaking, however, except in the case of a long thin magnet, the poles are not exactly at the ends. The middle line is called the neutral line or equator of the magnet; the straight line joining the poles is the axis of the magnet, or magnetic axis. A magnetic bar may abnormally have one or more intermediate points of maximum attraction, which are then called consequent poles. Again, if a magnetic needle is suspended at its center of gravity so as to be entirely free to turn, it is found that in general it places itself with its axis in a direction nearly north and south, and with one end inclining downward. The pole which is directed toward the north is called the north or north-seeking pole, also the boreal, positive, or red pole, or marked end of the needle; the other, the south, south-seeking, austral, negative, or blue pole, or unmarked end. It is found, further, that the like poles of two magnets repel and unlike poles attract each other. If a magnet is broken into halves, each half is found to be a complete magnet with a north and a south pole; and this is true no matter how often the process of division is repeated. On this and other more fundamental grounds, it is concluded that the magnetic polarity belongs to each molecule throughout the bar, and the maximum attraction observed near the ends is only the resultant effect of all these individual forces. (See magnetism.) A magnetic substance is one which may be attracted by a magnet, but has not the property of attracting other magnetic substances, and therefore has no polarity. Soft iron is a magnetic substance, as is also most magnetite, the lodestone variety being exceptional. A permanent magnet is one which retains its magnetism after the magnetizing influences (see below) cease to act. Steel and the lodestone have this property, on account of their high degree of coerciveforce. (See coercive.) Soft iron has very little coercive force, and accordingly its power of retaining magnetism is small. An artificial magnet (as a compass-needle)is made by contact with other magnets, and the methods employed are described as single-touch, double-touch, and separate-touch, according to the way in which the substance to be magnetized is rubbed by the magnets. Such a magnet may also be made by magnetic induction without actual contact. (See induction, 6.) Again, a magnet may be made by passing a current of electricity through a wire wound about the bar to be magnetized; this is called an electromagnet (which see). By this means magnets of very great strength may be made. They have usually a horseshoe form, and the bar is of soft iron, so that it retains its magnetism only so long as the current is passing. The earth may be considered as a huge magnet, whose poles are situated in the neighborhood of the geographical poles, though not coinciding with them; the north magnetic pole of the earth corresponds in polarity to the south-seeking pole of a magnetic needle. The action of the earth causes a freely suspended needle to set in a plane called the magnetic meridian, which in general makes an angle east or west of the geographical meridian (see declination), and with one pole (in the northern hemisphere, the north-seeking pole) inclined downward (see dip of the needle, under dip). The earth's magnetic force also serves to induce magnetism in masses of iron lying in or near the magnetic meridian. An iron ship is thus magnetized in the course of its construction. Similarly, iron columns, etc., are often found to be feebly magnetic. Magnetic properties belong also to some other compounds of iron besides the magnetic oxid, as pyrrhotite or magnetic pyrites (Fe₇S₈), and to some varieties of the native sesquioxid, hematite (Fe₂O₃); also to the magnetic metals nickel, cobalt, chromium, and manganese. Some varieties of platinum are strongly magnetic. and occasionally masses have polarity also, but this may be due to the large percentage of iron present, although all so-called iron-platinum does not show this property. Finally, it is found that a powerful electromagnet exerts an effect on all substances, in accordance with which they are divided into the two groups paramagnetic and diamagnetic (this is explained under diamagnetism).

Wiktionary

1. n. A piece of material that attracts some metals by magnetism.
2. n. informal, figuratively, preceded by a noun A person or thing that attracts what is denoted by the preceding noun.

GNU Webster's 1913

1. n. The loadstone; a species of iron ore (the ferrosoferric or magnetic ore, Fe3O4) which has the property of attracting iron and some of its ores, and, when freely suspended, of pointing to the poles; -- called also natural magnet.
2. n. (Physics) A bar or mass of steel or iron to which the peculiar properties of the loadstone have been imparted; -- called, in distinction from the loadstone, an artificial magnet.

WordNet 3.0

1. n. a characteristic that provides pleasure and attracts
2. n. (physics) a device that attracts iron and produces a magnetic field