(sports) A format of starting in certain racing sports, such as long-distance running, cycling and biathlon, where the competitors start at the same time and same place and proceed along the same course.

plural of mass driver

(aerospace) A proposed kind of electromagnetic catapult that could be used for space launches without the need for a rocket.

plural of weapon of mass destruction

(physics) The ratio of the average mass per atom of the naturally occurring form of an element to 1/12 of the mass of a carbon-12 atom. Symbol Aᵣ; abbreviation RAM or r.a.m. For elements with several isotopes, the most stable isotope is treated as the representative.

Any human-made weapon causing indiscriminate large-scale death or destruction, especially a biological weapon, chemical weapon, nuclear weapon or radiological weapon.

(chemistry) A unit of mass equal to 1/12 the mass of an atom of the ¹²C isotope of carbon.

(astronomy) a relationship that specifies the mass distribution of a newly formed stellar population

(mathematics) A function that gives the relative probability that a discrete random variable is exactly equal to some value.

The weighted average of the atomic masses of the naturally occurring isotopes of an element.