(set theory) The set that contains exactly those elements belonging to the universal set but not to a given set.

(physics) The coldest possible temperature, zero on the Kelvin scale, or approximately −273.15 °C, −459.67 °F; total absence of heat; temperature at which motion of all molecules would cease.

In Italian, Spanish, Portuguese, and Catalan: the form of an adjective formed by adding the suffixes -issimo, -ísimo, -íssimo, -érrimo, -imo, or -íssim to the adjective (with any final vowel dropped) to express a superlative that cannot be exceeded, having the sense “as ... as possible”.

(grammar) A construction in Latin and other sister languages in which an independent phrase with a noun in the ablative case has a participle, adjective, or noun, expressed or implied, which agrees with it in gender, number and case – both words forming a clause grammatically unconnected with the rest of the sentence.

(mathematical analysis) Of an infinite series: such that the sum of the absolute values of its summands converges.

(chemistry) Reasonably pure ethyl alcohol that contains at most 1% of water

(law) the official decree marking the legal end of a marriage, allowing the two people to remarry; it follows the decree nisi after six weeks (in Britain)

(mathematics) For a complex number a+bi, the principal square root of the sum of the squares of its real and imaginary parts, √. Denoted by | |.

(astronomy) The intrinsic luminosity that a celestial body would have if viewed from a distance of 10 parsecs or about 32.6 light years.

(meteorology) In a system of moist air, the ratio of the mass of water vapor present to the volume occupied by the mixture, that is, the density of the water vapor component. Absolute humidity is usually expressed in grams of water vapor per cubic meter or, in engineering practice, in grains per cubic foot. Because this measure of atmospheric humidity is not conservative with respect to adiabatic expansion or compression, it is not commonly used by meteorologists. (Also called vapor concentration and vapor density). See relative humidity.