An Etymological Dictionary of Astronomy and Astrophysics

A number representing a group of quantities, obtained by adding each quantity of the group and dividing the total by the number of quantities. Same as → arithmetic mean.

Etymology (EN): From O.Fr. avarie “damage to ship,” from It. avaria or maybe avere, O.Fr. aveir “property, goods,” from L. habere “to have.” Meaning shifted to “equal sharing of such loss by the interested parties.”

Etymology (PE): Miyângin “the middle; middle-sized; the middle pearl in a string,” from miyân, → middle, + -gin a suffix forming adjectives of possession.

A number representing a group of quantities, obtained by adding each quantity of the group and dividing the total by the number of quantities. Same as → arithmetic mean.

Etymology (EN): From O.Fr. avarie “damage to ship,” from It. avaria or maybe avere, O.Fr. aveir “property, goods,” from L. habere “to have.” Meaning shifted to “equal sharing of such loss by the interested parties.”

Etymology (PE): Miyângin “the middle; middle-sized; the middle pearl in a string,” from miyân, → middle, + -gin a suffix forming adjectives of possession.

Of a body traveling from A to B, the change of → velocity divided by the time interval: ā = (v₂ - v₁) / (t₂ - t₁).

See also: → average; → acceleration.

Of a body traveling from A to B, the change of → velocity divided by the time interval: ā = (v₂ - v₁) / (t₂ - t₁).

See also: → average; → acceleration.

The ratio of the displacement (Δx) of a particle, as it moves from point A to point B, to the corresponding time interval: v = Δx/Δt.

See also: → average; → velocity.

The ratio of the displacement (Δx) of a particle, as it moves from point A to point B, to the corresponding time interval: v = Δx/Δt.

See also: → average; → velocity.

The technique of looking slightly to the side of a faint object being studied while continuing to concentrate on the object. The technique helps bring out details which
otherwise would be missed by looking directly at an object. The reason is that the portion of the eye’s retina that best detects dim light (fovea) is located all around the edges rather than the center.

Etymology (EN): Averted p.p. from avert, from O.Fr. avertir, from L. avertere “to turn away,” from → ab- “from, away” + vertere “to turn” (cognate with Pers. gardidan “to turn”); → vision.

Etymology (PE): Negâh, → vision; kaž “averted.”

The technique of looking slightly to the side of a faint object being studied while continuing to concentrate on the object. The technique helps bring out details which
otherwise would be missed by looking directly at an object. The reason is that the portion of the eye’s retina that best detects dim light (fovea) is located all around the edges rather than the center.

Etymology (EN): Averted p.p. from avert, from O.Fr. avertir, from L. avertere “to turn away,” from → ab- “from, away” + vertere “to turn” (cognate with Pers. gardidan “to turn”); → vision.

Etymology (PE): Negâh, → vision; kaž “averted.”

The number of units in one → mole of any → substance (defined as its → molecular weight in grams), equal to 6.022 140 857 × 10²³. The units may be electrons, atoms, ions, or molecules, depending on the nature of the substance.

Etymology (EN): Named after Amedeo Avogadro (1776-1856), whose law allowed other physicists to calculate Avogadro’s number; → number.

The number of units in one → mole of any → substance (defined as its → molecular weight in grams), equal to 6.022 140 857 × 10²³. The units may be electrons, atoms, ions, or molecules, depending on the nature of the substance.

Etymology (EN): Named after Amedeo Avogadro (1776-1856), whose law allowed other physicists to calculate Avogadro’s number; → number.

A statement according to which equal volumes of different gases contain an equal number of molecules under the same conditions of temperature and pressure.

Etymology (EN): After Amedeo Avogadro (1776-1856), Italian chemist and physicist, who advanced the hypothesis in 1811.

A statement according to which equal volumes of different gases contain an equal number of molecules under the same conditions of temperature and pressure.

Etymology (EN): After Amedeo Avogadro (1776-1856), Italian chemist and physicist, who advanced the hypothesis in 1811.

→ Avogadro constant.

See also: Named after Amedeo Avogadro (1776-1856), whose law allowed other physicists to calculate Avogadro’s number; → constant.

→ Avogadro constant.

See also: Named after Amedeo Avogadro (1776-1856), whose law allowed other physicists to calculate Avogadro’s number; → constant.

1. To keep away from; keep clear of; shun.
   

   2. To prevent from happening (Dictionary.com). → abstain.

Etymology (EN): M.E. avoiden, from Anglo-French avoider “to clear out, withdraw (oneself),” from O.Fr. esvuidier “to empty out,” from es- “out,” → ex-, + vuidier “to be empty,” from voide “empty, vast, waste,” from L. vocivos “unoccupied, vacant,” vacare “be empty,” from PIE base *eue- “to leave, abandon, give out.”

Etymology (PE): Tosnidan, from Baluci tôsênag “avoid,” tusag “be quenched,” tôsaq “quench;” related to Pers. tohi “empty, void;” Mid.Pers. tuhig “empty;” Parthian tôšênitan “to empty;” cf. Pashto taš; Ormuri tusk; Waxi töš, təš; Sariqoli tīs; Skt. tucchá-, tucchyá- “empty;” L. tesqua “deserts;” O.Slav tušti “empty;” Russ. tošcij “meager.”

1. To keep away from; keep clear of; shun.
   

   2. To prevent from happening (Dictionary.com). → abstain.

Etymology (EN): M.E. avoiden, from Anglo-French avoider “to clear out, withdraw (oneself),” from O.Fr. esvuidier “to empty out,” from es- “out,” → ex-, + vuidier “to be empty,” from voide “empty, vast, waste,” from L. vocivos “unoccupied, vacant,” vacare “be empty,” from PIE base *eue- “to leave, abandon, give out.”

Etymology (PE): Tosnidan, from Baluci tôsênag “avoid,” tusag “be quenched,” tôsaq “quench;” related to Pers. tohi “empty, void;” Mid.Pers. tuhig “empty;” Parthian tôšênitan “to empty;” cf. Pashto taš; Ormuri tusk; Waxi töš, təš; Sariqoli tīs; Skt. tucchá-, tucchyá- “empty;” L. tesqua “deserts;” O.Slav tušti “empty;” Russ. tošcij “meager.”

Able to be avoided or prevented.

See also: → avoid; → -ance.

Able to be avoided or prevented.

See also: → avoid; → -ance.

The act of avoiding or keeping away from.

See also: → avoid; → -ance.

The act of avoiding or keeping away from.

See also: → avoid; → -ance.