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

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.

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

→ active; → sun.

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.

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

Agent noun from → activism.

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

Activity, from → active + -ity.

Žirandegi, noun from žirandé, → active.

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

→ act + → -or.

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").

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.

The act or process of actualizing.

Verbal noun of → actualize; → -tion.

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

→ actual; → -ize.

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."

The act or process of putting into action; activation.

Verbal noun of → actuate.

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

→ actuate; → -or.

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.).

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.

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. bé "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."

Addition of adjustments to a theory to save it from being falsified by compensating for anomalies not anticipated by the theory in its unmodified form. Theories that rely on continual, ad hoc adjustments are distrusted.

→ ad hoc; → hypothesis.

A fallacious objection to an argument or factual claim by appealing to a characteristic or belief of the person making the argument or claim, rather than by addressing the substance of the argument or producing evidence against the claim (wiktionary).

Literally "to a man," from → ad- "to," + hominem, accusative of homo "man," → human.

Pad mart, literally "to a man," from pad "to," → ad hoc, + mart, → man.

To make suitable to or fit for a specific use or situation.

From M.Fr. adapter, from L. adaptare "adjust," from ad- "to" + aptare "join," from aptus "fitted."

Niyâvidan from Mid. Pers. niyâw "apt, suitable, appropriate" + -idan verb making suffix.

Capable of adapting or of being adapted.

→ adapt + → -able.