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

An → adaptive optics instrument used on the → European Southern Observatory (ESO) 3.6-m telescope at La Silla. It was an upgraded version of COME-ON-PLUS, the → Very Large Telescope (VLT) adaptive optics prototype. It had 52 → actuators and performed corrections of the mirror 200 times per second. The reference → wavefront was sensed in the → visible. The observation was done in the → near-infrared (1-5 μm).

→ adaptive; → optics; → near-infrared; → system.

An → optical system that uses → adaptive optics.

→ adaptive; → optics; → system.

1) To unite or so as to bring about an increase.
2) To increase a number by another number using addition, which leads to a → sum.

M.E. adden, from L. addere "add to, join," from → ad- "to" + -dere combining form meaning "to put, place," from dare "to give, grant," from PIE base *do- "to give" (cf. Av. and O.Pers. dâ- "to give, grant, yield," Av. dadâiti "he gives," Skt. dadâti "he gives," Gk. didomi "I give," L. do "I give").

Bardâyidan, from bar- "on; up; upon; in, into; at; forth," → on-, + O.Pers./Av. dā- "to give, grant, put," dadāiti "he gives;" Mid.Pers./Mod.Pers. dâdan "to give, put" (cf. Skt. dadáti "he gives;" Gk. tithenai "to place, put, set," didomi "I give;" L. dare "to give, offer;" Rus. delat' "to do;" O.H.G. tuon, Ger. tun, O.E. don "to do;" PIE base *dhe- "to put, to do") + -y-, epenthetic vowel, + infinitive suffix -idan.
Afzudan, → increase.

A number or quantity to be added to another. In the expression 5 + 3, both 5 and 3 are addends.

From L. addendus "that which is to be added," → add.

Bardâyé, from present stem bardây-, → add, + noun forming suffix -é.

The operation of combining two or more quantities to obtain a third quantity called their → sum. The result of adding.

Verbal noun of → add.

The → plus sign +. It is believed to be a shortened form of the letters e and t in the L. word et, which, in early German manuscripts was the term for addition. The signs + and - were first used by Johann Wiedmann in 1489.

→ addition; → sign.

1) Involving → addition.
2) Something added to a substance to alter or improve it.

From L. additivus "added, annexed," from p.p. stem of addere, → add; → -ive.

1) Related to bardâyeš, → addition; 2) from bardây- prsent stem of bardâyidan, → add, + -é nuance suffix.

Color created by mixing light rays of different colors. Combining all the color rays of light results in white light. See also → subtractive color.

→ additive; → color.

The number which can be added to any other number without changing the magnitude of that number: zero. → multiplicative identity.

→ additive; → identity.

If E₁, E₂, ..., E_n are n → mutually exclusive events, then the probability of occurrence of at least one of them is the sum of their individual probabilities: P(E₁ + E₂ + ... + E_n) = P(E₁) + P(E₂) + ... + P(E_n).

→ additive; → law; → probability.

A binary star, in the constellation → Canis Major, 470 → light-years distant from Earth. The main star possesses an apparent magnitude of +1.5 and belongs to the spectral classification B2 II. The +7.5 magnitude companion star is 7''.5 apart from the main star.

Adhara, from Ar. adhârâ "virgins," plural of adhrâ' "virgin".

Azârâ, from Ar. Adhara.

1) To stay attached; stick fast; cling.
2) Physics: (of two or more dissimilar substances) to be united by a molecular force acting in the area of contact (→ adhesion).

From M.Fr. adhérer or directly from L. adhaerere "to stick to," from → ad- + haerere "to stick."

Âdusidan, from intensive/nuance prefix â- + dusidan (Dehxodâ) "to stick, to adhere," maybe related to Proto-Ir. *dauc- "to sew;" Pers. duxtan, duz- "to sew."

1) The act or state of adhering; adhesion.
2) The quality of adhering; steady devotion, support, or attachment (Dictionary.com).

→ adhere + -ence, → -ance.

1) A person who follows or upholds a leader, cause, etc.; supporter; follower.
2) Sticking; clinging; adhering (Dictionary.com).

From O.Fr. adherent or directly from L. adhaerentem pr.p. of adhaerere "to stick to," → adhere.

Âdusandé, from âdusidan, → adhere.

1) The act or state of adhering; state of being adhered or united.
2) Steady or devoted attachment, support, etc.; adherence.
3) Physics: The molecular force of attraction in the area of contact between unlike bodies that acts to hold them together (Dictionary.com). See also → cohesion.

Verbal noun from → adhere; → -tion.

1) Of or pertaining to the molecular force → adhesion.
2) A substance used for sticking objects or materials together; glue.

Adjective from → adhere.

The force of → attraction between molecules of different substances; for example, the force between the molecules of a solid and a liquid. When water is poured on clean glass, it tends to spread, forming a thin, uniform film over the surface. This is because the adhesive forces between water and glass are strong enough to pull the water molecules out of their spherical formation and hold them against the surface of the glass, thus avoiding the repulsion between like molecules.

→ adhesive; → force.

A → late-type → giant star of → spectral type K0-IIIb in → Andromeda. Other designations: ξ (Xi) Andromedae, HR 390, and HD 8207. → Visual magnitude = 4.88, B - V = +1.08.

From Ar. Al-dhayl "skirt of a garment; tail."

A → thermodynamic process that occurs without → loss or → gain of → heat.
See also: → adiabatic change, → adiabatic index, → adiabatic initial conditions, → adiabatic phase, → adiabatic process, → adiabatic shock, → adiabatic temperature gradient, → superadiabatic temperature gradient.

From Gk. adiabatos "impassable," from a- "not" + diabatos "passable," from diabainein "to go across," from dia- " through" + bainein "to go."

Bidarrow from bi- "not; without" + darrow "way out," from dar "out" + row "to go, going," from raftan "to go."

A change taking place in a system that has perfect thermal insulation, so that heat cannot enter or leave the system and energy can only be transferred by work.

→ adiabatic; → change.