A quantity that is characteristic of a charge distribution, equal to the vector sum over the electric charges of the product of the charge and the position vector of the charge.

1. A vector equal to the product of the magnitude of either of two charges of equal magnitude but opposite in their polarity and the distance between their centers.
2. One of a series of quantities characterizing an electric charge distribution.

A quantity that describes an electric charge distribution, determined by integrating the product of the charge density, the third power of the distance from the origin, and a spherical harmonic over the charge distribution.

A quantity characterizing an electric charge distribution, obtained by integrating the product of the charge density, the second power of the distance from the origin, and a spherical harmonic over the charge distribution.

1. A measure of the magnetic strength of a magnet or a current-carrying coil, expressed as the torque produced when the magnet or coil is set with its axis perpendicular to unit magnetic flux density which is measured in ampere meters squared.
2. The magnetic moment of a current-carrying coil, equal to the product of the current, the number of turns, and the area of the coil.
3. The vector magnetic moment of a current-carrying coil, equal to the product of the current, the number of turns, and the area of the coil.

The direction is given by the right-hand rule (right hand rule) or hand rule, which refers to a current-carrying wire where the rule is that if the fingers of the right hand are placed around the wire so that the thumb points in the direction of current flow, the fingers will be pointing in the direction of the magnetic field produced by the wire.

1. The total amount of polarization (dipole moment) caused by the movement of electrons within an atom.
2. The magnetic dipole moment which an electron possesses by virtue of its spin.
3. The total magnetic dipole moment associated with the orbital motion of all the electrons of an atom and the electron spins.

This is opposed to a nuclear magnetic moment.

A measure of the size of an earthquake based on the area of fault rupture, the average amount of slip, and the force that was required to overcome the friction sticking the rocks together that were offset by faulting. Seismic moment can also be calculated from the amplitude spectra of seismic waves.

A "slip" is the relative displacement of formerly adjacent points on opposite sides of a fault, measured on the fault surface.

The "spectrum" is a curve showing amplitude and phase as a function of frequency or period, or how much of each type of shaking there is from an earthquake.

A temporary lapse of memory as a person ripens in age: The couple in their golden years realized that they were often experiencing senior moments because they couldn't always remember some well-known word or name when they were talking to each other.

Rick Perry, a 65-year-old governor of Texas and a Republican candidate for President of the U.S. in 2011, apparently had a senior moment or "brain freeze" when he stopped in mid-sentence while struggling to remember the name of the Department of Energy as one of three federal agencies he had often said should be eliminated.

Perry's senior moment resulted in a pained look on his face as he stammered and started over again but he still couldn't remember what he wanted to say; so, he changed the subject after a 53 second senior moment.