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

Any salt of perchloric acid.

→ per-; → chlorate.

A colorless liquid, HClO₄, that reacts explosively with organic matter or other reducible materials.

→ perchlorate; → -ic; → acid.

1a) Corresponding to an ideal standard or abstract concept.
1b) Exactly fitting the need in a certain situation or for a certain purpose.
2) To bring to perfection or completion. See also: → perfect cosmological principle, → perfect cube, → perfect gas, → perfect lens, → perfect number, → perfect power, → perfect set, → perfect square.

From M.E. parfit, from O.Fr. parfit, from L. perfectus "completed," p.p. of perficere "accomplish, finish, complete," from per- "through, thoroughly, utterly, very" + facere "to make, do, perform;" cognate with Pers. dâdan "to give" (O.Pers./Av. dā- "to give, grant, yield," dadāiti "he gives;" 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").

Farsâxt, farsâz, literally "thorougly made," from far- intensive prefix "much, abundant; elegantly" (Mid.Pers. fra- "forward, before; much; around;" O.Pers. fra- "forward, forth;" Av. frā, fərā-, fra- "forward, forth; excessive;" cf. Skt. prá- "before; forward, in fron;" Gk. pro "before, in front of;" L. pro "on behalf of, in place of, before, for;" PIE *pro-) + sâxt, sâz "made," short for sâxté, sâzidé "made; make, construction, structure; style," present stem of sâxtan, sâzidan "to build, make, fashion; to adapt, adjust, be fit" (from Mid.Pers. sâxtan, sâz-, Manichean Parthian s'c'dn "to prepare, to form;" Av. sak- "to understand, to mark," sâcaya- (causative) "to teach").

The → assumption, adopted by the → steady-state theory, that all observers, everywhere at all times, would view the same large-scale distribution of matter in the → Universe in all regions and in every direction. In contrast to the → cosmological principle, the perfect cosmological principle adds the assumption that the Universe does not change with time on the large scale.

→ perfect; → cosmological; → principle.

An → integer of the form n³, where n is a → positive number. In other words, a → perfect power when k = 3.

→ perfect; → cube.

A hypothetical gas with molecules of negligible size that exert no intermolecular forces. Also called → ideal gas.

→ perfect; → gas.

A theoretical, ideal lens capable of producing perfect images. Used as a lens design and analysis tool to image collimated output from an afocal system.

→ perfect; → lens.

An → integer that is equal to the → sum of its → positive  → divisors, not including itself. For example 6, because its positive divisors are 1, 2, and 3, and 1 + 2 + 3 = 6. Two other examples are 28 and 496.

→ perfect; → number.

A → positive integer that can be expressed as an integer → power of another positive → integer. For example, n is a perfect power if there exist natural numbers m> 1, and k> 1 such that m^k = n. → perfect cube, → perfect square.

→ perfect; → power.

A set P is called perfect if P = P', where P' is the derived set of P.

→ perfect; → set.

An → integer of the form n², where n is a → positive number. In other words, a → perfect power when k = 2.

→ perfect; → square.

Capable of becoming or of being made perfect.

→ perfect; → -able.

The state or quality of being or becoming perfect.

→ perfect; → -tion.

1) Any of various doctrines holding that religious, moral, social, or political perfection is attainable.
2) A personal standard, attitude, or philosophy that demands perfection and rejects anything less (Dictionary.com).

→ perfection; → -ism.

1) A person who adheres to or believes in → perfectionism.
2) A person who demands perfection of himself, herself, or others (Dictionary.com).

→ perfection; → -ist.

1) To carry out; → execute; do.
2) To go through or execute in the proper, customary, or established manner (Dictionary.com).

M.E. parformen, from Anglo-Fr. performer, from O.Fr. parfornir "to do, carry out, finish, accomplish," from par- "completely," → per-, + fornir "to provide."

Pergâlidan, from Kurd. (Sanandaj) pergâl "work, doing; order, command," ultimately from Proto-Ir. *parikar-, from *pari- "through, throughout; thoroughly" (O.Pers. pariy "around, about;" Av. pairi "around, over") + *kar- "to do;" Pers. kar-, variants kâr, gar, gâr, → work.

1) The act of performing a ceremony, play, piece of music, etc.
2) The execution or accomplishment of work, acts, feats, etc.
3) A musical, dramatic, or other entertainment presented before an audience (Dictionary.com).

→ perform; → -ance.

1) Relating to or of → performance, especially of dramatic or artistic performance.
2) A → performative utterance.

→ perform; → -ive.

A sentence or expression which is not only describing a given reality, but actually does or accomplishes something. For example "I now declare you husband and wife" (when uttered by the authorized officiator during a marriage ceremony).

→ performative; → utterance.

1) Someone who performs in front of an audience, for example an actor or musician.
2) Someone who does something with a particular amount of success (Macmillan Dictionary).

→ perform; → -er.