(mathematics) The path traced by the instantaneous centre of a rotating three-dimensional body moving relative to an inertial frame of reference

The region of space containing objects that an optical system can form images of.

(physics) The localized excess electric charge in a specific volume; especially such a negative charge

(biology) Any of various biological sciences that deal with living things in a space environment

The loss of energy of a signal (due to absorption, dispersion etc) as it travels through a medium; measured in decibels

The environment encountered by living creatures (and vehicles) in space; especially a lack of atmosphere and gravity

A mental representation of a particular problem, including initial, final and possible intermediate states

Alternative spelling of space defense

(in an electromagnetic coil) The ratio of the volume occupied by the wire in the winding, or the iron in the core, to the total volume of the winding or the core

Any defensive measure against an attack by missiles etc while in space