Collectively, the communications media, especially television, radio, and newspapers, that reach the mass of the people.

(physics, analytical chemistry) An analytical technique that measures the mass / charge ratio of the ions formed when a molecule or atom is ionized, vaporized and introduced into a vacuum. Mass spectrometry may also involve breaking molecules into fragments - thus enabling its structure to be determined.

plural of mass extinction

(evolutionary theory, geology) A sharp decrease in the total number of species in a relatively short period of time; specifically, a loss of ∼75% of all species on the planet over a geologically interval of less than 3 million years, as a result of a mass extinction event.

(physics, chemistry) The total number of protons and neutrons in an atomic nucleus. Symbol: A

(physics) The increased mass of an object moving at relativistic speed relative to an observer.

(physics) The mass of a body when it is not moving relative to an observer.

(chemistry) The mass of an individual molecule of an element or compound.

(physics) The amount of fissile material needed to support a self-sustaining nuclear chain reaction. / (figuratively) The tipping point.

(military) A body of troops held in military reserve by a general for striking a blow on an exposed flank or wherever the enemy reveals a weak spot.