(relativity) A theory extending special relativity and uniformly accounting for gravity and accelerated frames of reference, postulating that space-time curves in the presence of mass.

(meteorology) The ratio of the actual amount of water vapor (absolute humidity) present in the air to the saturation point at the same temperature, usually expressed as a percentage.

(grammar) A relative pronoun used in an adjectival clause.

(grammar) A pronoun that introduces a relative clause and refers to an antecedent. Some words that can be used as interrogative pronouns can alternatively be used as relative pronouns: what, which, who, and whom. The other relative pronouns are whoever, whomever, whatever, and that.

(sciences) A measure of the density of a material. The ratio of the density of a substance to the density of water at the same temperature. It is dimensionless and therefore has no units.

(grammar) A subordinate clause that modifies a noun.

(grammar) the superlative (a degree of comparison) when it is used to express the highest degree of something in relation to something else

(physics) The theories of special relativity and general relativity, two theories in physics developed mainly by Albert Einstein at the beginning of the 20th century from which several important results such as the equivalence of matter and energy and the Einstein field equations are derived.

(topology) subspace topology

plural of relative pin