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

The act of adopting. The state of being adopted.

→ adopt; → -tion.

Of or involving adoption. Acquired or related by adoption.

→ adopt; → -ive.

The second innermost known satellite of Jupiter, whose orbit is situated at a distance of about 129 000 km from the planet, and its orbital period is of 0.298 days; also known as Jupiter XV. Adrastea is 25 x 20 x 15 km in size.

In Gk. mythology, Adrastea was the daughter of Zeus and Ananke and the distributor of reward and punishments.

To take up and hold another substance on the surface.

→ adsorption.

1) A material that can hold or condense molecules of another substance on its surface by adsorption.
2) Relating to or capable of adsorption.

From → adsorb + →-ent.

Baršamandé, from baršamidan, → adsorb, + -andé.

A process in which a layer of atoms or molecules of one substance forms on the surface of a solid or liquid. → absorption, → desorption, → sorption.

Adsorption from ad- "to" + sorption, from L. sorbere "to suck," → absorption.

Baršam, from bar- "on, upon" + šam "to drink, sip," → absorption.

1) A person who is fully grown or developed or of age.
2) Having attained full size and strength; grown up; mature. A person who has attained the age of maturity as specified by law (Dictionary.com).

From L. adultus "grown up, mature, adult, ripe," p.p. of adolescere "to grow up, mature," from → ad- "to" + alescere "be nourished," from alere "to nourish."

Bornâ, from Mid.Pers. purnây- "adult;" Av. pərənāyu- "adult, old;" (Baluchi warnâ "adolescent"), literally "of full age," from pərəna-, → full, + āyu- "age," → aeon.

The slow rotation of the major axis of a planet's orbit in the same direction as the revolution of the planet itself, due mainly to gravitational interactions with other planets. The perihelion of the planet Mercury advances about 9'.6 per century. The bulk of the advance was accounted by perturbations from other planets. However, a remaining small advance, by 43'' per century, was eventually explained as an effect predicted by Einstein's theory of → general relativity. In the case of close binary stars, the advance of pericenter may additionally be caused by mass transfer and the stars' distorted (elliptical) shapes. Advance of perihelion (or pericenter) is also known as → apsidal motion.

Advance, from O.Fr. avancer "move forward," from V.L. *abantiare, from L.L. abante "from before," from ab- "from" + ante "before," PIE *ant- "front, forehead;" → perihelion.

Pišraft "advance," from piš "forward; in front; before," Mid.Pers. peš + raft "going; walk, travel," from raftan "to go."

A wave that travels backward in time according to Maxwell's electromagnetic theory; it arrives before it is transmitted. → Maxwell's equations have two solutions, the normal solution describes the ordinary waves, called → retarded waves, traveling forward in time. However, no advanced waves have ever shown up in any experiment. The advanced solutions of Maxwell's equations are usually simply discarded as "unphysical."

Advanced, adj. from advance, → advance of perihelion; → wave.

Mowj, → wave; pišras "advanced," from piš "before," Mid.Pers. peš + ras "arriving," from rasidan "to arrive," Mid.Pers. rasitan, O.Pers./Av. rasa- present stem of ar- "to move, go or come toward," cf. Skt. ar-, rcchati.

1) Geology: The process of transport of a quantity by the velocity field due to the movement of a fluid. Advection differs from → convection, which describes thermally driven circulation.
2) Meteorology: The predominantly horizontal, large-scale motions of the atmosphere. In contrast, convection describes the predominantly vertical, locally induced motions.

From L. advecti "act of conveying," from advectus, past participle of advehere "to carry," from ad-, "to" + vehere "to carry, bring;" Skt. vah-, vahati "to carry, conduct, guide," Av. vaz-, vazaiti "to guide, lead"; PIE *wegh- "to go, transport in a vehicle".

Pahnbaz from pahn "flat, wide, → broad," + baz "to carry," → evection.

The first term on the right side in the → induction equation.

→ advection; → term.

Adj. from → advection.

A word that serves to qualify a verb, an adjective, another adverb, or an entire sentence. More specifically, adverbs indicate manner, time, place, cause, or degree, and answer questions such as "how," "when," "where," "how much."

From L.L. adverbium "adverb," literally "that which is added to a verb," from → ad- "to" + verbum "word, → verb," a translation of Gk. epirrhema "adverb," from → epi- "upon, on" + rhema "verb."

Apivâz, from api-, → epi-, + vâz "word," → verb.

1) A person, group, or force that opposes or attacks; opponent; enemy; foe.
2) A person, group, etc., that is an opponent in a contest; contestant (Dictionary.com).

M.E. adversaire; O.Fr. adversaire "opponent, adversary, rival," from L. adversarius "opposite, hostile, contrary," from adversus "turned against," from → ad- + verse, → universe.

Hamestâr, from Mid.Pers. hamestâr "adversary," from Av. hamaēstar-, from ha-, → com-, + maēd- "to bring down, to suppress."

A round vessel pivoted on a central axis that rotates by the force of internal steam escaping from two diametrically opposed narrow apertures. Aeolipile, first described by Hero of Alexandria (c. 10-70 AD), is an early example of → jet propulsion.

L aeolipila, from Gk aiolipyle, from Aiolon pyle, fr. aioli-, from Aiolos "god of wind," + pyle "gate."

1) General: An indefinitely long period of time; an age.
2) Geology: A unit of geologic time equal to one billion years; US eon.

L. aeon, from Gk. aion "age, eternity;" akin to Av. āiiu- "duration, period, lifetime;" Skt. áyu- "life, longevity."

Âyu, from Av. āiiu- "duration, period, lifetime" (Sogd. āy "life, age"), as above.

Of or pertaining to → aerodynamics.

→ aerodynamics.

The force exerted by a gaseous fluid upon a body completely immersed in it caused by their relative motion. The components of aerodynamic force are: → lift and → drag.

→ aerodynamic; → force.

The science that is concerned with the study of the → motion of → air and other gaseous → fluids and with the → forces acting on bodies moving through such fluids.

Aerodynamics, from Gk. aero-, → air, + → dynamics.

A stony meteorite consisting of silicate minerals. This alternative name for a stony meteorite, is now largely obsolete.

Aerolite, from Gk. aero-, → air, + Gk. lithos "stone".

Havâsang from Persian havâ "air"; compare with Mid. Pers./Mod. Pers. vây "weather," from Av. vayah-, vaya- "weather, atmosphere," from va- "to blow". Cognate with Skt. va-, Gk. aemi "to blow" + sang, → stone.