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

Chemistry: The number of covalent bonds which an atom can from. The sharing of electrons to form chemical bonds. → equivalence.

From → co- + valence, from L. valentia "strength, worth," valere "to be worth; be strong."

Ham-arzâyi, from ham-→ co- + arzâyi, from arzidan "to be worth," arzân "worthy; of small value, cheap," arj "esteem, honour, price, worth," Mid.Pers. arz "value, worth," arzidan "be worth," arzân "valuable;" Av. arəjaiti "is worth," arəja- "valuable," arəg- "to be worth;" cf. Skt. arh- "to be worth, to earn," árhant- "worthy person;" Gk. alphanein "to bring in as profit," alphein "to ear, obtain;" Lith. algà "salary, pay;" PIE base *alg^wh- "to earn; price, value."

The → equivalence principle as stated by Einstein, on which is based the theory of → general relativity. It comprises the three following items:
1) The → weak equivalence principle is valid.
2) The outcome of any local non-gravitational experiment is independent of the velocity of the freely-falling → reference frame in which it is performed. Also known as → local Lorentz invariance.
3) The outcome of any local non-gravitational experiment is independent of where and when in the Universe it is performed. Also called → local position invariance.

→ Einstein; → equivalence; → principle.

The state or fact of being equivalent; equality in value, force, significance, etc. → covalence.

From M.F. from M.L. æquivalentia, from L. æquivalent-, → equivalent.

Hamug-arzi, noun of hamug-arz, → equivalent.

A fundamental concept of physics, put forward by A. Einstein, that states that gravitational and inertial forces are of a similar nature and indistinguishable. In other words, acceleration due to gravity is equivalent to acceleration due to other forces, and gravitational mass is the same as inertial mass. Same as the → principle of equivalence.

→ equivalence; → principle.

The principle of interconversion of mass and energy, described by the → mass-energy relation.

→ mass; → energy; → equivalence.

In → general relativity the principle which states that in the immediate proximity of an → accelerating system the acceleration is physically equivalent to → gravitational force. This principle also implies the equivalence of → gravitational mass and → inertial mass. Same as the → equivalence principle. See also → Einstein's elevator.

→ principle; → equivalence.

A measure of the number of chemical bonds formed by the atoms of a given element. It represents the relative ability of an atom of an element to combine with other atoms. For example, the valence of O in water, H₂O, is 2. Also called valency.

M.E., from O.Fr., from L valentia "strength, worth," from valentem (nominative valens), pr.p. of valere "to be strong."

Arzâyi, noun from arzâ, agent noun/adj. from arzidan "to be worth," arzân "worthy; of small value, cheap," arj "esteem, honour, price, worth" (Mid.Pers. arz "value, worth," arzidan "be worth," arzân "valuable;" Av. arəjaiti "is worth," arəja- "valuable," arəg- "to be worth;" cf. Skt. arh- "to be worth, to earn," árhant- "worthy person;" Gk. alphanein "to bring in as profit," alphein "to ear, obtain;" Lith. algà "salary, pay;" PIE base *alg^wh- "to earn; price, value").

The range of energy states in the spectrum of a solid crystal which includes the energies of all the electrons binding the crystal together.

→ valence; → band.

An electron of an atom lying farthest from the nucleus. Valence electrons are shared when atoms combine to form molecules.

→ valence; → electron.

All structureless bodies fall along the same → path in a → gravitational field, independent of their composition. Also known as → universality of free fall. See also: → equivalence principle, → Einstein equivalence principle.

→ weak; → equivalence; → principle.