(logic) The operator, represented by the symbol ∀, used in predicate calculus to indicate that a predicate is true for all members of a specified set.

(theology) The idea, particularly in Christianity, that an opportunity to follow the deity, e.g. Jesus, will be an option at the time of death.

A measure of time that conforms, within a close approximation, to the mean diurnal rotation of the Earth and serves as the basis of civil timekeeping.

(uncountable) A branch of mathematics dealing with equational classes of algebras, where similar theorems from disparate branches of algebra are unified.

A coupling that allows different parts of a machine not in line with each other some freedom of movement at the same time as transmitting rotary motion.

plural of universal donor

(medicine) A person with blood type O, which lacks antigens and is therefore compatible with all other blood types, allowing them to donate blood to any other person.

(mathematics) The property of there being a unique morphism from an arbitrary object to the universal morphism of a comma category which is from a functor to a fixed object; or, dually, the property of there being a unique morphism from the universal morphism to an arbitrary object of a comma category which is from a fixed object to a functor. (Caveat: the uniqueness is up to isomorphism.)

A universal proposition in logic.

(linguistics) A mechanism whereby countable nouns are made uncountable.