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

An array of numbers in the shape of a triangle, having a 1 at the top and also at the ends of each row. Each number is obtained by summing the two adjacent numbers to it in the preceding row. Each row is a set of → binomial coefficients. In the expansion of (x + y)ⁿ, the coefficients of x and y are given by the n-th row of Pascal's traingle.

→ pascal; → triangle.

The spectral series associated with the third energy level of the hydrogen atom. The series lies in the infrared, with Pα at 18,751 Å, and Paschen limit at 8204 Å.

In honor of Friedrich Paschen (1865-1947), German physicist; → series.

An effect on spectral lines obtained when the light source is located in a strong magnetic field. The strong field disrupts the coupling between the orbital and spin angular momenta, resulting in a different pattern of splitting.

Named for the German physicists Friedrich Paschen (1865-1947) and Ernst E. A. Back (1881-1959); → effect.

The fifteenth of Jupiter's known satellites, orbiting at 23,660,000 km from Jupiter; also known as Jupiter VIII. Its diameter is 36 km and orbital period 744 days.

In Gk. mythology, Pasiphae was the wife of Minos and mother, by a white bull, of the Minotaur.

An act or instance of passing from one place, condition, etc., to another; transit. Same as → transit.

M.E, from O.Fr. passage, from passer "to go by;" originally "a road, passage."

Gozar "passage, transit, passing," from gozaštan "to pass, cross, transit," variant gozâštan "to put, to place, let, allow;" Mid.Pers. widardan, widâštan "to pass, to let pass (by);" O.Pers. vitar- "to pass across," viyatarayam "I put across;" Av. vi-tar- "to pass across," from vi- "apart, away from" (O.Pers. viy- "apart, away;" Av. vi- "apart, away;" cf. Skt. vi- "apart, asunder, away, out;" L. vitare "to avoid, turn aside") + O.Pers./Av. tar- "to cross over;" → trans-.

The range of wavelengths that are transmitted by a filter. Same as → band-pass.

Pass from O.Fr. passer, from V.L. *passare "to step, walk, pass," from L. passus "step, pace;" cf. Pers. pâ "foot," pey "step;" → band.

Gozar "passage, transit, passing," from gozaštan "to pass, cross, transit," variant gozâštan "to put, to place, let, allow;" Mid.Pers. widardan, widâštan "to pass, to let pass (by);" O.Pers. vitar- "to pass across," viyatarayam "I put across;" Av. vi-tar- "to pass across," from vi- "apart, away from" ( O.Pers. viy- "apart, away;" Av. vi- "apart, away;" cf. Skt. vi- "apart, asunder, away, out;" L. vitare "to avoid, turn aside") + O.Pers./Av. tar- "to cross over"); bând, → band.

Tending not to participate actively; not working or operating.

From L. passivus "submissive; capable of feeling or suffering," from passus, p.p. of pati "to experience, undergo, suffer."

Akâr "not working, not doing," from → a- negation prefix + kâr "work," varaint of kar, present stem of kardan "to do, to make" (Mid.Pers. kardan; O.Pers./Av. kar- "to do, make, build;" Av. kərənaoiti "he makes;" cf. Skt. kr- "to do, to make," krnoti "he makes, he does," karoti "he makes, he does," karma "act, deed;" PIE base k^wer- "to do, to make").

A cumulus cloud that is no longer dynamically connected with the atmospheric boundary layer via updrafts or downdrafts.

→ passive; → cloud.

An electronic component which contains no source of power, in contrast to active components.

→ passive; → component.

A galaxy lacking optical emission-line activity (e.g., [O II], Hα, [O III]) and showing only stellar absorption lines (e.g., the 4000 Å → calcium break, Mg I, Na I). Also called passively evolving galaxy.

→ passive; → galaxy.

An electronic system which emits no energy, and is not detectable.

→ passive; → system.

Same as → passive galaxy.

→ passive; → evolve; → galaxy.

An arbitrary string of characters chosen by a user or system administrator and used to authenticate the user when he attempts to log on, in order to prevent unauthorised access to his account (foldoc.org).

Pass, → passage; → word.

Of, having existed in, or having occurred during a time previous to the present; bygone (Dictionary.com).

M.E.; variant spelling of passed, p.p. of pass, from O.Fr. passer, from V.L. *passare "to step, walk, pass," from L. passus "step, pace;" cf. Pers. pâ "foot," pey "step," → foot.

Gozašté, p.p. of gozaštan "to pass," → passage.

A → participle that indicates a completed action or state.

→ past; → participle.

1) A small piece of material used to mend a tear or break, to cover a hole, or to strengthen a weak place.
2) A piece of material used to cover or protect a wound, an injured part, etc.
3) A small piece, scrap, or area of anything (Dictionary.com). → bald patch; → patchy turbulence.

M.E. pacche; of uncertain origin.

Pac, from Bašgaridi (Giroft) pac "patch; fragment," probably from *parka-, from *par- "piece" + diminutive/relation suffix -ka; cf. pâré "piece, part, portion;" parré "portion, segment (of an orange);" pargâlé "piece, portion; patch;" Kermâni pariké "portion, half;" Tabari perik "minute quantity, particle;" Lârestâni pakva "patch;" Borujerdi parru "patch;" (Fin Bandar Abbâs) park "patch;" (Tâti) pajina "patch, darn;" → part.

A → turbulence that is not continuous in space, but is separated by regions of stability and → laminar flow.

Patchy adj. of → patch; → turbulence.

A shallow dish-like crater with irregular, sometimes scalloped rims, on the surface of a planet.

From L. patera "abroad, shallow dish" (used for drinking, primarily in a ritual context).

1) A route, course, or track along which something moves.
2) A course of action, conduct, or procedure.
3) Math.: A continuous curve that connects two or more points.
4) In → graph theory, a → graph whose → vertices can be arranged in a sequence.

O.E. paþ, pæþ; cf. O.Fris. path; M.Du. pat; Du. pad; O.H.G. pfad; Ger. Pfad "path."

Pah "path, way," from O.Pers. paθi- "path, way;" Av. paθ-, variants paθi-, paθā-, pantay- (with conversion of -θ- to -h-, as in ciθra-/cehr, xšaθra-/šahr/šâh, vərəθraγna-/bahrâm, → Mars); Mid/Mod.Pers. pand "path, advice, counsel;" Khotanese pande "road, path;" Ossetic fœndœg "path, road;" cf. Skt. pánthā- "road, path, course;" Gk. patos "path, way," pontos "sea;" L. pons "bridge, path;" P.Gmc. *finthanan "to find;" E. find; PIE base *pent- "to go, to tread."
Râh, → way.

The path followed by an individual particle of fluid over an interval of time. It contrasts with the → streamline that represents an instantaneous picture of the motion of particles.

→ path; → line.