This article is about the electromagnetic phenomenon. From the point of
view of the mathematics of distributions, a dipole can be taken
to be the directional derivative of a Dirac delta function. A
dipole is also a type of radio antenna.

The Earth's magnetic
field, which is approximately a dipole.

However, the "N" and "S"
(north and south) poles are labelled here geographically,

which is the opposite of
the convention for labelling the poles of a magnetic dipole moment.

A dipole (Greek:
di(s) = double and polos = pivot) is a pair of
electric charges or magnetic poles of equal magnitude but opposite
polarity (opposite electronic charges), separated by some (usually
small) distance. Dipoles can be characterized by their dipole
moment, a vector quantity with a magnitude equal to the product of the
charge or magnetic strength of one of the poles and the distance
separating the two poles.

The direction of the dipole
moment corresponds, for electric dipoles, to the direction from the
negative to the positive charge. For magnetic dipoles, the dipole
moment points from from the magnetic south to the magnetic north pole —
confusingly, the "north" and "south" convention for magnetic dipoles is
the opposite of that used to describe the Earth's geographic and
magnetic poles, so that the Earth's geomagnetic north poleis
the south pole of its dipole moment. (Because of the absence of
magnetic monopoles, magnetic dipoles are actually created by
current loops and/or by quantum-mechanical spin.)

Since the direction of an electric field is defined as the direction of
the force on a positive charge, electric field lines point away from a
positive charge and toward a negative charge.