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

The → rate at which → work is done by a → force. In other words, → mechanical energy per unit time. Mechanical power is expressed in units of joules/sec (joules/s) or a watt (W) in the → mks system.

→ mechanical; → power.

1) Any system of elements that interact according to the laws of → mechanics (as distinguished from chemical, electrical, thermal, etc.).
2) A collection of → machines functioning together to achieve the transfer of motion.

→ mechanical; → system.

A process in which matter is shed into a → Keplerian disk from a star rotating at the → critical velocity. The disk is probably destroyed by the pressure exerted by the stellar radiation and finally matter is lost. Such a process seems to occur around → Be stars which are stars rotating at or very near the critical limit (Meynet et al. 2007, arXiv:0709.2275).

→ mechanical; → wind.

1) In a mechanical manner; by a mechanism.
2) In a machine-like manner; without feeling.

→ mechanical; → -ly.

A person skilled in constructing, working, or repairing machines; mechanic; machinist (Dictionary.com).

From → mechanic + -ian.

A branch of → physics that deals with motion and the → action of → forces on bodies. Mechanics may be divided into three areas, → kinematics, → dynamics, and → statics.

From mechanic, from L. mechanicus, from Gk. mekhanikos "an engineer," also "inventive," literally "pertaining to machines" (adj.), from mekhane, → machine, + → -ics.

Mekânik, loan from Fr. Sâzokârik, from sokâr, → mechanism, + -ik, → -ic.

1) The structure or arrangement of parts of a machine or similar device, or of anything analogous.
2) The agency or means by which an effect is produced or a purpose is accomplished.

From Mod.L. mechanismus, from Gk. mekhane, → machine.

Sâzokâr, literally "making and working," from sâz "apparatus; (musical) instrument," from sâzidan, sâxtan "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") + kâr "work," from 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").

Statistics: The middle value in a sample sorted into ascending order. If the sample contains an even number of values, the median is defined as the mean of the middle two.
Geometry: The line from a vertex of a triangle to the midpoint of the opposite side.

From M.Fr. médian, from L. medianus "of the middle," from medius "middle;" akin to Pers. middle, → medium, → meddle; from PIE *medhyo-, from base *me- "between;" → medium.

Miyâné from miyân, → middle, + -é nuance suffix.

The art or science of restoring or preserving health or due physical condition, as by means of drugs, surgical operations or appliances, or manipulations (Dictionary.com).

M.E. medicin, from O.Fr. medecine "art of healing, cure," from L. medicina "the healing art; a remedy," feminine of medicinus (adj.) "of a doctor," from medicus "a physician;" PIE root *med- "to measure, limit, consider, advise," → dimension; cf. Av. vi-mad- "physician;" Gk. medein "to rule;" L. meditari "think or reflect on, consider," → meditation; Ir. miduir "judge;" O.E. metan "to measure out."

Pezeški, from pezešk "physician," from Mid.Pers. bizešk "physician," bêšâz "medicinal;" Av. bišaz- "to cure, heal;" cf. Skt. bhisaj- "healer, physician."

To engage in thought or contemplation; reflect. → consider.

Back formation from → meditation.

Segâlidan "to meditate, consider, think," from Mid.Pers. uskaridan "to think, consider, discuss," from us-, → ex-, + kar- "to observe, to consider;" related to engâridan, negaristan, âgâridan, → consider.

The act of meditating. → consideration.

From L. meditatatus p.p. of meditari "to think over, reflect, consider," from PIE root *med- "to measure, limit, consider, advise," → mode.

Verbal noun of → meditate.

An intervening substance through which an effect is produced; surrounding objects, conditions, or influences; environment. → interstellar medium.

From L. medium, from neut. of adj. medius "middle," from PIE *medhyo- "middle;" cf. Av. maδəma- "middle," as below.

Madim, from Av. maδəma- [adj.] "middle, being in the middle; middling, of a middling size or quality," maiδim "in the midst of," maiδyāna- "the middle;" cf. Skt. mádhya- "middle;" Gk. messos; Goth. midjis; O.E. midd "middle;" O.C.S. medzu "between," Arm. mej "middle;" L. medium, as above.

To come upon; come into the presence of; encounter.

M.E. meten, from O.E. metan "to find, find out; encounter; obtain," cognate with O.Frisian meta, O.Sax. motian "to meet," Goth. gamotijan, ultimately from PIE root *mod- "to meet, assemble."

Mavâzidan, from Sogd. mwz "to meet together, encounter" (Cheung 2007); ultimately from Proto-Ir. *ham-uaz-, from *ham- "together, → com-," + *uaz- "to move, carry, drive;" cf. Av. vaz- "to move, carry, drive (a chariot);" Pers. vazidan "to blow;" parvâz "→ flight."

1) The act of coming together.
2) An → assembly or conference of persons for a specific purpose (Dictionary.com).

→ meet; → -ing.

1) Prefix, often meaning "large, great."
2) Prefix meaning 10⁶.

From Gk. megas "great, large, mighty," from PIE *meg- "great;" cf. L. magnus, Goth. mikils, O.E. micel.

A unit of distance equal to a million → parsec (pc)s, or 3.26 million → light-years.

→ mega-; → parsec.

Same as → Dyson sphere.

→ mega-; → structure.

A unit of explosive force equal to one million metric tons of → T.N.T.. 1 megaton = 4.2 × 10²² → ergs = 4.2 × 10¹⁵ → joules.

→ mega-; → ton.

One of the seven stars of the → Big Dipper, which links Ursa Major's tail to the Bear's hindquarters. Megrez is the dimmest of the Big Dipper stars at magnitude +3.3. It is an A3 dwarf, about 20 times more luminous that the Sun, lying 81 light-years away.

From Ar. al-Maghriz(المغرز) "the root, base, bottom" (of the Bear's tail).

A → giant star of → apparent visible magnitude 3.54 in the → Orion constellation. λ Ori is of → spectral type O8 III, has a mass of about 28 → solar masses, a size of about 10 → solar radii, and an → effective temperature of around 35,000 K. Meissa is a → soft X-ray source with a → luminosity of 10³² erg s^-1 and peak emission in the energy range of 0.2-0.3 keV, which is probably generated by the → stellar wind. Meissa is a member of the → Orion OB1 association. It is in fact a → double star with a → companion at an angular separation of 4.41 arcseconds. This fainter component has a magnitude of 5.61, is a → main sequence star of → spectral type B0.5 V. There is an outlying component, Meissa C, which is an F-type main sequence F8 V star. This star in turn may have a very low mass companion that is probably a brown dwarf. λ Ori, excites a fairly symmetric → H II region, Sh2-264 surrounding it. Many observational studies have found dark clouds external to this H II region.

Arabic al-maysan (مَیسان) "bright."