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

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 926
active galactic nucleus (AGN)
  هسته‌ی ِ کهکشان ِ ژیرا   
haste-ye kahkašân-e žirâ

Fr.: noyau actif de galaxie   

A central region of an → active galaxy, which is a → light-year or less in diameter and has an abnormally high luminosity. The nucleus emits high energy radiation (→ gamma rays, → X-rays, → ultraviolet) and shows → variability over various time-scales, sometimes very short (hours to weeks). Emission line spectra reveal high velocity motions up to 104 km s-1. AGNs are divided into two main types. Type I refers to an AGN whose nucleus is visible (the spectra has both narrow and broad emission lines), while in type II AGN, the broad line region (BLR) is obscured and the lines are very narrow. This may be due either to the viewing angle or some intrinsic difference in structure. See also → broad-line region, → narrow-line region, → quasar.

active; → galactic; → nucleus.

active galaxy
  کهکشان ِ ژیرا   
kahkašân-e žirâ

Fr.: galaxie active   

A galaxy that produces huge amounts of energy at its center, which cannot be attributed to normal processes from stars, interstellar medium, and their interactions. There are several types of active galaxies: → Seyfert galaxies, → quasars, and → blazars. All of these objects show brightness variations, some as short as 3 hours. These fluctuations indicate a relatively very small size for the central object, because an object cannot vary in brightness faster than light can travel across it. For example, an object that is one → light-year in diameter cannot vary significantly in brightness over a period of less than one year.

active; → galaxy.

active optics
  نوریک ِ ژیرا   
nurik-e žirâ

Fr.: optique active   

A technique for improving the → resolving power of a telescope by controlling the shape of the main mirror at a relatively slow rate. The → image quality is optimized automatically through constant adjustments by in-built corrective → actuators operating at fairly low temporal frequency ~0.05 Hz or less. → adaptive optics.

active; → optics.

active prominence
  زبانه‌ی ِ ژیرا   
zabâne-ye žirâ

Fr.: protubérance active   

A solar → prominence with very rapid motion (up to 2,000 km s-1), moving and changing in appearance over a few minutes of time, in contrast to a → quiescent prominence.

active; → prominence.

active region
  ناحیه‌ی ِ ژیرا   
nâhiye-ye žirâ

Fr.: région active   

An area of the Sun exhibiting → solar activity with the presence of → sunspots, → flares, → faculae, → prominences, and other phenomena associated with intense magnetic fields.

active; → region.

active sun
  خورشید ِ ژیرا   
xoršid-e žirâ

Fr.: soleil actif   

The Sun during its 11-year cycle of activity when spots, flares, prominences, and variations in radiofrequency radiation are at a maximum.

active; → sun.

activism
  ژیرش‌باوری، ژیرش‌کاری   
žireš-bâvari, žireš-kâri

Fr.: activisme   

1) The doctrine or practice of vigorous action or involvement as a means of achieving political or other goals, sometimes by demonstrations, protests, etc. (Dictionary.com). See also → activist.
2) Philosophy: a) A theory that the essence of reality is pure activity, especially spiritual activity, or process. b) A theory that the relationship between the mind and the objects of perception depends upon the action of the mind (Dictionary.com).

active; → action; → -ism.

activist
  ژیرش‌باور، ژیرش‌کار   
žireš-bâvar, žireš-kâr

Fr.: activiste   

An especially active, vigorous advocate of a cause, especially a political cause (Dictionary.com).

Agent noun from → activism.

activity
  ژیرایی، ژیرندگی   
žirâyi, žirandegi

Fr.: activité   

For a radioactive substance, the average number of atoms disintegrating per unit time.

Activity, from → active + -ity.

Žirandegi, noun from žirandé, → active.

actor
  ژیرنده   
žirandé

Fr.: acteur   

1) One who takes part; a participant.
2) A theatrical performer.

From → act + → -or.

Žirandé adj./noun from žir, → act + suffix -andé. Žirmand, from žir + mand.

actual
  ژیروند   
žirvand

Fr.: actuel   

1) Existing in act or fact; real.
2) Philosophy: The character of what is realized in act (such as a statue), as opposed to what can potentially be realized (from a piece of rock).

M.E. actuel, from O.Fr. actuel "now existing, up to date," from L. actualis "active, pertaining to action," adj. form of actus, → act.

Žirvand, from žir, → act, + -vand a suffix forming adjectives denoting "possessed of, similarity, relation," variants -âvand, -van (e.g. xodâvand "possessor, master," pulâdvand "hard as steel, name of a hero," dowlatvand "rich," setarvan "mule-like, barren," polvan "bridge-like, a raised path"), from Mid.Pers. -âwand (hunarâwand "skilled," warzâwand "powerful"); Av. -vant (aurvant- "swift," surunvant- "audible"); cf. Skt. -vant (amavant- "having attacking power").

actuality
  ژیروندی   
žirvandi

Fr.: actualité   

1) The quality or state of being actual or something that is actual; reality.
2) Philosophy: According to Aristotle, what has → form and can causally interact with other things, as opposed to → potentiality.

actual; → -ity.

actualization
  ژیروندش، ژیروند‌کرد   
živandeš, živandkard

Fr.: actualisation   

The act or process of actualizing.

Verbal noun of → actualize; → -tion.

actualize
  ژیروندیدن، ژیروند کردن   
živandidan, živand kardan

Fr.: actualiser   

To make actual or real; turn into action or fact.

actual; → -ize.

actuate
  برژیریدن   
baržiridan

Fr.: actionner, déclencher   

1) To put into mechanical action or motion.
2) To incite or move to action; motivate.

From L. actuatus, p.p. of actuare, from actus, → act.

Baržiridan, from bar- "on, upon, up," → on-, + žiridan "to → act."

actuation
  برژیرش   
baržireš

Fr.: actionnement, déclenchement   

The act or process of putting into action; activation.

Verbal noun of → actuate.

actuator
  برژیرگر   
baržirgar

Fr.: actuateur   

A mechanism to activate process control equipment by use of pneumatic, hydraulic, or electronic signals.

actuate; → -or.

acuity
  تیزنایی   
tiznâyi (#)

Fr.: acuité   

Sharpness; acuteness; keenness of perception.

M.E., from M.Fr. acuité, from M.L. acuitatem (nom. acuitas) "sharpness," from L. acus "needle," acuere "to sharpen," from PIE root *ak- "be sharp."

Tiznâ "sharpness," from tiz, "→ sharp," + -nâ, a suffix that transforms adjective into noun (compare with tangnâ, derâznâ, farâxnâ, etc.).

acuity of vision
  تیزنایی ِ دید   
tiznâ-ye did

Fr.: acuité visuelle   

The ability of the → eye to see separately two points close to each other. It is a measure of the → resolving power of the eye's → optical system and depends on the density of cells in the → retina. The maximum acuity of the normal human eye is around 0.5 minutes of arc.

acuity; → vision.

ad hoc
  پدیم   
pad im

Fr.: ad hoc   

For the specific purpose at hand, as opposed to a general solution; also, by extension, improvised or impromptu.

From L. ad "to, with, in," cf. Skt. adhi "near," PIE *ad- "to, near, at."

Pad im, from Mid.Pers. pad "to, at, for, in" (Mod.Pers. "to, for, in, on, with, by"); O.Pers. paity "agaist, back, opposite to, toward, face to face, in front of;" Av. paiti "to, toward, in, at;" cf. Skt. práti "toward, against, again, back, in return, opposite;" Pali pati-; Gk. proti, pros "face to face with, toward, in addition to, near;" PIE *proti) + Mid.Pers. im "this;" from Old.Pers./Av. ima "this;" Skt. imá; cf. Lori (Laki) im "this side." The Mid.Pers. im occurs in Mod.Pers. as em- in emruz "today," emšab "tonight," and emsâl "this year."

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