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

Of or pertaining to a state, value, or quantity that is less than critical, especially the condition of a → subcritical reactor.

→ sub-; → critical.

An amount of → fissile material that by its mass or geometry is incapable of sustaining a → fission → chain reaction.

→ subcritical; → mass.

A → nuclear reactor in which the rate of production of → fission neutrons is lower than the rate of production in the previous generation, and therefore the number of fissions decreases over time.

→ subcritical; → reactor.

Geology: The process by which one tectonic plate slides down and below another tectonic plate as the two converge. The subduction zone is the zone of convergence of two tectonic plates, one of which usually overrides the other.

From L. subductionem (nominative subductio), from subductus, p.p. of subducere "to draw away, withdraw, remove," from → sub- + ducere "to lead."

Zir-hâzeš, verbal noun of zir-hâzidan, from zir-→ sub- + hâzidan, hâxtan, from Mid.Pers. "to lead, guide, persuade;" Av. hak-, hacaiti "to attach oneself to, to join;" cf. Skt. sacate "accompanies, follows;" Gk. hepesthai "to follow,"; L. sequi "to follow;" PIE *sekw-.

A metal-poor main-sequence star with spectral type later than M7 and luminosity class VI. They are population II dwarfs which appear less luminous than their solar metallicity counterparts due to the dearth of metals in their atmospheres. Subdwarfs are halo members with high proper motions and large heliocentric velocities. They are important tracers of the chemical enrichment history of the Galaxy and belong to the first generation of stars formed in the Galaxy (at least 10 billion years old).

→ sub-; → dwarf.

A star with a lower absolute magnitude than a normal giant star of its → spectral type. It is a star that has exhausted the hydrogen at its center and is evolving into a → red giant. Subgiants are luminosity class IV.

→ sub-; → giant.

1) Something that is being discussed, examined, or otherwise dealt with.
2) A branch of learning that forms a course of study.
3) Philosophy: That which thinks, feels, perceives, intends, as contrasted with the objects of thought, feeling, etc.
4) Grammar: The part of a sentence or clause referring to the person or thing that does or causes the action of a verb. In English, the subject is typically a noun ("The cat ..."), a noun phrase ("His father's first trip ..."), or a pronoun ("It ...").

M.E. suget, from O.Fr. suget, subget "a subject person or thing," from L. subjectus "placed beneath, inferior, open to inspection," noun use of p.p. of subicere "to place under," from → sub-"under" + combining form of jacere "to throw,"from PIE base *ye- "to do" (cf. Gk. iemi, ienai "to send, throw," Hitt. ijami "I make").

Darâxt "thing drawn in, under" from dar- + âxt. The prefix dar-, from preposition dar "in, into, within; on, upon, above; of, about, concerning;" from Mid.Pers. andar "in, into, within," → inter-.
The second component âxt, contraction of âxté, p.p. of âxtan, variants âhixtan, âhiz- "to draw (a sword)," âhanjidan "to draw up, pull, extract," Mid.Pers. âhixtan, âhanjitan "to draw out, pull up, extract," Av. θanj- "to draw, pull, drive;" Proto-Iranian *θanj-.
Karin, from Sogd. karênê (variant kunênê) "doer, maker," from kar-, kardan "to do, to make," → -or.

1) That which depends upon the personal or individual, especially where it is supposed to be an arbitrary expression of private taste, in contrast with the objective.
2) Grammar: Pertaining to or constituting the subject of a sentence.

Adjective of → subject.

1) The state or quality of being → subjective. Contrasted with → objectivity.
2) The interpretation based on individual personal feelings and opinions rather than on external → facts.

→ subjective + → -ity.

The process whereby a substance goes from a solid directly to a gaseous form.

From M.L. sublimationem (nominative sublimatio) "refinement," literally "a lifting up, deliverance," from L. sublimare "to raise, elevate," from sublimis "lofty."

Vâlâyeš, verbal noun from vâlâ "sublime, majestic," may be a variant of bâlâ "up, above, high, elevated, height," variants boland "high," borz "height, magnitude" (it occurs also in the name of the mountain chain Alborz), Lori dialect berg "hill, mountain;" Mid.Pers. buland "high;" O.Pers. baršan- "height;" Av. barəz- "high, mount," barezan- "height;" cf. Skt. bhrant- "high;" L. fortis "strong" (Fr. & E. force); O.E. burg, burh "castle, fortified place," from P.Gmc. *burgs "fortress;" Ger. Burg "castle," Goth. baurgs "city," E. burg, borough, Fr. bourgeois, bourgeoisie, faubourg); PIE base *bhergh- "high."

A star that is less luminous than a main-sequence star of the same spectral type.

→ sub-; → luminous; → star.

(Adj.) Located, occurring, operating, or living beneath the surface of the → sea.

→ sub- + → marine.

Geology: A long, steep elevation of the deep sea floor.

→ submarine; → ridge.

Hydrology: A freshwater spring that emerges off the seashore.

→ submarine; → spring.

1) To sink or plunge under water or beneath the surface of any enveloping medium.
2) To cover or overflow with water; immerse (Dictionary.com).

From L. submergere, from → sub- + mergere "to dip, immerse;" probably by rhotacism from PIE *mezg- "to dip, plunge;" cf. Skt. majj- "to sink in water;" Lith. mazgoju "to wash."

Marcidan, from Av. mraoc- "to float, submerge;" cf. Skt. mroc/mloc "to go down, set (of the Sun), to disappear, to hide;" Kurd., Laki, Nahâvandi, Bovir-Ahmadi mala- "swim," Kurd. melâna "ship, boat," melaq "wave" may be related to this Av. form.

Of or pertaining to scales smaller than millimeter.

→ sub-; → millimeter.

The study of astronomical objects with → submillimeter waves. As with millimeter-wave astronomy, this part of the spectrum is rich in lines emitted by interstellar molecules and dust.

→ submillimeter; → astronomy.

A member of an extremely luminous population of → high-redshift galaxies which are detected in → submillimeter waves (→ flux density at 850 μm ≥ 3 - 5 mJy). SMGs are powered primarily by star formation rather than an → active galactic nucleus (AGN). Because of their high → dust content, these galaxies emit almost all of their luminosity in the infrared, with a → bolometric luminosity ranging from 10¹²-10¹³ → solar luminosities. As such, SMGs resemble → ultraluminous infrared galaxies (ULIRGs), which are almost exclusively → merging galaxies. Indeed, many observations support a → merger origin for SMGs (see, e.g. C.C. Hayward et al. 2011 and references therein, astro-ph/1101.0002).

→ submillimeter; → galaxy.

That part of the → electromagnetic radiation with a → wavelength beyond 300 → microns.

→ submillimeter; → radiation.

An electromagnetic wave having wavelengths less than one millimeter (frequencies greater than 300 gigahertz).

→ millimeter; → wave.