The word dipole refers to two poles and is used to
describe electric fields and magnetic fields that
are organized around two locations of opposite polarity.
In contrast, multipole indicates more locations, e.g.,
some of each polarity. For example, a planet's
magnetic field can be basically a dipole overall, yet in detail be
multipole if there are spots on the surface where one or the other
polarity is strong.
The word dipole has other related uses, such as to describe
antennas (dipole antenna, which creates or senses a
dipole electric field),
and in mathematics as a subclass of coefficients of a
multipole expansion.