An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

Having boundaries; limited. → closed curve; → closed Universe.

Closed, p.p. of close, from M.E. clos, from O.Fr., from clore "to shut," from L. clausus, p.p. of claudere "to close."

Basté p.p.of bastan, from Mid.Pers. bastan/vastan "to bind, shut," Av./O.Pers. band- "to bind, fetter," banda- "band, tie," Skt. bandh- "to bind, tie, fasten," PIE *bhendh- "to bind," cf. Ger. binden, E. bind, → band.

A curve whose ends are joined.

→ closed; → curve.

A bounded space the surface of which has the property that if one travels in any direction upon it without changing direction, one will end up back to the departure point. An example is a sphere. Triangles which lie on the surface of a closed space will have a sum of angles which is greater than 180°. An closed space has a positive → curvature. See also → closed Universe, → open space.

→ closed; → space.

Thermodynamics: A system which can exchange energy with the surroundings but not matter. → open system; → isolated system.

→ closed; → system.

A → cosmological model, first formulated by Friedmann and Lemaître, in which the Universe has a → finite size and lifetime and → space has a → positive → curvature, e.g. a Universe with a density greater than the → critical density. See also → closed space.

→ closed; → Universe.

In → predicate logic, a → wff with no → free occurrences of any → variable. Also called a → sentence.

→ closed; → wff.

A subsystem if its intrinsic energy is large, on the average, with respect to the energy of its interaction with other portions of the → closed system.

→ quasi-; → closed; → subsystem.