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

An expression specifying the number of meaningful digits used to express the value of a measured quantity. Same as accurate to n significant figures. For example, e = 2.71828 ... = 2.718 is rounded to four significant digits, and 2.72 to three significant digits. → accurate to n decimal places.

→ accurate; → significant; → digit.

The → plus sign +. It is believed to be a shortened form of the letters e and t in the L. word et, which, in early German manuscripts was the term for addition. The signs + and - were first used by Johann Wiedmann in 1489.

→ addition; → sign.

1) To give or allocate; allot.
2) To give out or announce as a task.
3) To designate; name; specify (Dictionary.com).

M.E. assignen, from O.Fr. assiginer "assign; appoint legally; allot," from L. assignare "to mark out, to allot by sign," from → ad- "to" + signare "to make a sign," from signum "mark," → sign

Nešârdan, from neš, → sign, + nuance suffix -âr.

1) An appointment for a meeting.
2) The act of assigning; → assignment (Dictionary.com).

Verbal noun of → assign.

1) An act of assigning; appointment.
2) Something assigned, as a particular task or duty.
3) A position of responsibility, post of duty, or the like, to which one is appointed (Dictionary.com).

Verbal noun of → assign.

1) For an asteroid whose orbit is precisely known, a number and optionally a proper name, e.g. (7) Iris, (24101) Cassini, (99942) Apophis.
2) For an asteroid whose orbit is not known, a provisional designation composed of four elements: number.letter.letter.(optionally)number. The first number indicates the year of discovery. The first letter denotes the half-month of the discovery (A: first half of January, Y: second half of December; the letter "I" is excluded). The second letter and the following number indicate the order of discovery within the half-month. For example, the first asteroid discovered in the first half of May 1960 is: 1960 JA. Since more than 25 objects (without "I") might be detected within a half-month, the number following the second letter indicates the number of 25 discoveries. Hence, 2001 SD3 was discovered in the second half of September 2001 and was the (D =) 4 + (25 x 3) or the 79th object found during that period.

→ asteroid; → designation.

A stellar designation system in which a specific star is identified by a Greek letter, followed by the genitive form of its hosting → constellation's Latin name. For example, Alpha Eridani, Delta Cephei, Lambda Bootis. The Greek alphabet has only 24 letters. In case a single constellation contained a larger number of stars, Bayer amended with Latin letters: upper case A, followed by lower case b through z (omitting j and v), for a total of another 24 letters. Bayer did not go beyond z, but later astronomers added more designations using both upper and lower case Latin letters, the upper case letters following the lower case ones in general. Examples include, for Vela: a Vel (Velorum), z Vel, A Vel, Q Vel; for Scorpius: d Sco (Scorpii), A Sco; for Leo: b Leo (Leonis), o Leo, A Leo, → c Orionis. Compare with the → Flamsteed designation.

First introduced by Johann Bayer (1572-1625) in his atlas Uranometria, published in 1603 at Augsburg, Germany; → designation.

A substance or phenomenon whose presence in an object such as a → meteorite or an → exoplanet indicates the existence of life.

→ bio-; → signature.

A → nomenclature system for naming → comets. In early 1995, a new comet designation system was established by the → International Astronomical Union. The main rules are as follows:
a) If the comet is a newly discovered one, it first gets a provisional name, which closely matches the → asteroid designation system. For example, the first comet discovered in the first half of 1998 January is designated 1998 A1, the second 1998 A2, etc.
b) The name of the person(s) who discovered the comet may be added to this designation (limited, however, to three names). For example, comet → Hale-Bopp (C/1995 O1) has its full name as Hale-Bopp C/1995 O1, whereas its designation is C/1998 O1. If several people are involved with a discovery at an observatory, the comet may be named after the observatory instead of the individuals.
c) → Long-period comets and one-apparition → periodic comets receive only a provisional designation.
d) A → short-period comet would get the P/designation until it is recovered in a second → apparition. At this point, the P/Year designation would be replaced with a number followed immediately by an upper case P, and a slash followed by the name of the discoverer(s). The number here is one more than the number of known periodic comets that have reappeared. For example, the comet Hug-Bell (P/1999 X1) was given the full name 178P/Hug-Bell after it reappeared in 2007. Previously, 177 periodic comets had got assigned numbers.
e) Long-period comets are indicated by the prefix C.
f) If the comet is destroyed, or if it fails to appear after several apparitions, it would be prefixed D/ (→ defunct comet) followed by the year of its discovery. For example, → Comet Shoemaker-Levy 9 has been assigned D/1993 F2 since it was discovered in the second half of March in 1993 and was destroyed when it crashed into Jupiter in 1994.
g) Comets that lack sufficient position measurements for an orbital determination are given the designation of X/ followed by the year of their discovery and the appropriate letter and number code.
h) When a → comet nucleus nucleus splits, each fragment is given the comet designation followed by A, B, C, etc (for fragments).

→ comet; → designation.

1a) An outline, sketch, or plan, as of the form and structure of a work of art, an edifice, or a machine to be executed or constructed.
1b) Organization or structure of formal elements in a work of art; composition.
2a) To prepare the preliminary sketch or the plans for (a work to be executed), especially to plan the form and structure of.
2b) To plan and fashion artistically or skillfully.
2c) To intend for a definite purpose (Dictionary.com).

M.E. designen, from M.Fr. desseign "purpose, project, design," from It. disegno, from disegnare "to mark out," from L. designare "mark out, devise, designate, appoint," from → de- "out" + signare "to mark," from signum "a mark, → sign."

Barsé, related to (Delijâni) barsi "to throw," variants baysi, vaesi, deresi; (Xonji, Gerâši) bar-, barressa "to fall down;" ultimately from Proto-Ir. *garH- "to throw;" cf. (+*ni-) Av. niγr- "to throw down;" Khotanese bīr- "to throw, sow;" Pers. garzin "a pointed arrow;" Pashto qoer "jump, leap," aqar "fitting an arrow to the bow-string ready to shoot;" cf. Skt. gar- "to raise a weapon;" Gk. ballein "to throw," → problem, blema "projectile;" PIE root *g^welH- "to throw" (Cheung 2007). Barsé is coined on the model of Ger. Entwurf "design; project" and entwerfen "to design," from werfen "to throw;" Pers. dar-andâxtan "to propound, to pose" (Hâfez: falak râ saxt beškâfim o tarhi now dar-andâzim); also Ar. tarh (طرح) "to throw."

A distinctive name or title; appellation. → Bayer designation; → Flamsteed designation; → variable star designation.

From L. designatus, p.p. of designare "to mark out, choose, appoint," from → de- "out" + signare "to mark," from signum, → sign.

Nâmgozini, from nâm, → name, + gozini "choosing," from gozidan "to chose," → select.

A person who devises or executes designs, especially one who creates forms, structures, and patterns, as for works of art or machines (Dictionary.com).

→ design; → -er.

A symbol placed between two quantities (dividend and the divisor) to indicate the division of the first by the second. The division sign is written as a horizontal line with dot above and dot below, ÷ (→ obelus), or a slash or horizontal line.

→ division; → sign.

Information transmitted by means of a modulated current or an electromagnetic wave and received by telephone, radio, television, etc.

→ electromagnetic; → signal.

Same as → equals sign.

→ equality; → sign.

A mathematical symbol (=) that indicates equality of two expressions on each side of the sign. Same as → equality sign. The equals sign appears for the first time in Robert Recorde's book The Whetstone of Witte published in 1557. He was a Welsh physician and mathematician.

→ equal; → sign.

A stellar designation system in which each star is assigned a number followed by the Latin genitive of its corresponding → constellation, such as → 61 Cygni and 82 Eridani. Compare with the → Bayer designation.

Named after John Flamsteed (1646-1719), founder of the Greenwich Observatory, and the first astronomer royal of England, who introduced this system in his catalog Historia Coelestis Britannica (1725); → designation.

A galaxy with prominent → arms that are clearly attached to the central → bulge or → bar spiraling continuously outward until they reach the edge of the visible disk. Some examples are: → Whirlpool galaxy (M51), M74 (NGC 628), and NGC 2997.

M.E. graunt, from O.Fr. grant, grand, from L. grandis "big, great," also "full-grown;" design, from M.E. designen, from L. designare "mark out, designate, appoint," from → de- "out" + signare "to mark," from signum→ sign; → spiral; → galaxy.

Kahkešân, → galaxy; mârpic→ spiral; farsâz, → perfect.

Same as → significance level.

→ level; → significance.

The sign used to indicate multiplication, either a times sign (×), a centered dot (·), or an asterisk. The multiplication sign was introduced by William Oughtred in 1631.

→ multiplication; → sign.