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

In the → phase diagram of a → mixture at constant pressure, (such as an → alloy), the → curve that separates the → liquid+solid → phase from the all solid phase. Above the solidus some or all of the mixture will be in a liquid state. See also → liquidus.

From L. solidus, → solid.

Math., Physics: A solution of a certain type of partial differential equation that represents a solitary wave. A soliton is a self-reinforcing wave that maintains its shape while it travels at constant speed. Solitons are caused by a cancellation of nonlinear and dispersive effects in the medium.

From solit(ary) + → -on.

Either of the two points on the → ecliptic at which the apparent → longitude of the → Sun is 90° or 270°. Also the time at which the Sun is at either point. Solstices occur when the Earth's axis is oriented directly toward or away from the Sun, causing the Sun to reach its northernmost and southernmost extremes. → summer solstice, → winter solstice.

M.E., from O.Fr. solstice, from L. solstitium "point at which the sun seems to stand still," from sol, → sun, cognate with Pers. xor, xoršid, hur, as below, + p.p. stem of sistere "to come to a stop, make stand still," akin to Pers. istâdan "to stand," as below.

Xoristân, is composed of two components. The first one xor "sun," variant hur; Mid.Pers. xwar "sun;" Av. hū-, hvar- "sun;" cf. Skt. surya-, Gk. helios, L. sol, cognate with E. sun, as above; PIE base *sawel- "sun." The second component istân "standing," from istâdan "to stand;" Mid.Pers. êstâtan; O.Pers./Av. sta- "to stand, stand still; set;" Av. hištaiti; cf. Skt. sthā- "to stand;" Gk. histemi "put, place, weigh," stasis "a standing still;" L. stare "to stand;" Lith. statau "place;" Goth. standan; PIE base *sta- "to stand."

The great circle of the celestial sphere which passes through the poles of the celestial equator and the solstice points. → equinoctial colure.

Solsticial, adj. of → solstice; → colure.

The two points of the ecliptic the most distant from the equator.

Solsticial, adj. of → solstice; → point.

Chem.: Capable of being dissolved .

M.E., from M.Fr. soluble, from L.L. solubilis "that may be loosened or dissolved," from stem of L. solvere "loosen, dissolve," → solve.

Luyidani, from luyidan, → solve + -i, → -able.

Chem.: A substance which is dissolved in a solvent to form a solution.

From L. solutus, p.p. of solvere "to loosen, dissolve," → solve.

Luyešt, from luyešte, p.p. of luyeštan, variant of luyidan, → solve.

1) The act of solving a problem, question. The state of being solved.
2a) Math.: The process of determining the answer to a problem. The answer itself.
2b) Math.: Of a differential equation, any function which, when put into the equation, converts it into an identity.
3) Chem.: The process by which a gas, liquid, or solid is dispersed homogeneously in a gas, liquid, or solid without chemical change. a homogeneous, molecular mixture of two or more substances.

Verbal noun of → solve.

Any of a class of chemical reactions in which solute and solvent molecules combine.

From solv(ent), → solvent + -ation.

Luyé, from luy- the stem of luyidé→ solute and luyandé→ solvent + -é nuance suffix.

1) To find an answer or solution to; clear up; explain. related concept: → dissolve.
2) To make a solution of, as by mixing with liquid.

M.E. solven, from L. solvere "to loosen, dissolve, untie," from PIE *se-lu-, from reflexive pronoun *swe- + base *leu- "to loosen, divide, cut apart;" cf. Gk. lyein "to loosen, release, untie," O.E. -leosan "to lose," leas "loose;" E. lose, loose and Ger. los derive from this root.

Luyidan, infinitive from stem lu(y)-, from lu, variant of Mod.Pers. las "loose," lâ "slit, cut," luš "torn," lok "torn, piece," lâc "open, wide open;" lu, lunoti "to cut, sever, mow, pluck, tear asunder, destroy," lava "cutting, plucking; what is cut; fragment, piece;" Gk. lyein "to loosen, release, untie," as above. PIE *leu- "to loosen, divide, cut apart".

Substance having the power of dissolving other substances in it.

Agent noun of → solve.

A → spiral galaxy in the constellation → Virgo. It was the first galaxy whose rotation was detected. Also named M104 and NGC 4594.

Sp. sombrero "broad-brimmed hat," originally "umbrella or parasol," from sombra "shade," from L.L. subumbrare, from → sub- "under" + umbra "shade, shadow;" → galaxy.

Kahkešân, → galaxy; sombrero, Sp., as above.

A rocket or balloon carrying instruments to probe conditions in the upper atmosphere.

From Fr. sonde "ounding line; plumb line."

Gomâné "a shaft sunk in order to ascertain the depth of the water when making a subterraneous canal," from Proto-Iranian *vi-mā-, from vi- "apart, away from, out" (cf. Av. vi-; O.Pers. viy- "apart, away;" Skt. vi- "apart, asunder, away, out;" L. vitare "to avoid, turn aside") + mā- "to measure" (cf. O.Pers./Av. mā(y)- "to measure;" Mod.Pers. mâ/mun/mân "measure," as in Pers. terms âzmâ- "to test;" pirâmun "perimeter," âzmun "test, trial," peymân "measuring, agreement," peymâné "a measure; a cup, bowl;" PIE base *me- "to measure;" cf. Skt. mati "measures," matra- "measure;" Gk. metron "measure;" L. metrum).

Of, relating to, or being the speed of sound in a medium.

From L. sonus, → sound.

Sedâyi, pertaining to sedâ, → sound.

A noise caused by a shock wave that emanates from an object traveling at or above the speed of sound.

→ sonic; boom, M.E. bombon, bummyn "to buzz;" cf. Du. bommen, Ger. bummen, word made by sound imitation.

Qariv "shout, clamour, cry;" sedâyi, → sonic.

The point where the → stellar wind makes a transition from → subsonic to → supersonic flow. In the particular case of a spherically symmetric wind (thus with no magnetic field), the distance from star, at which the sonic point occurs, is given by: r_s = (GM_*)/2c_s², where G is the → gravitational constant, M_* is the stellar mass, and c_s the → sound speed at the sonic point.

→ sonic; → point.

To gather on a surface either by absorption, adsorption, or a combination of the two processes.

Verb, from sorption, extracted from → absorption→ adsorption, from L. sorbere "suck in," from PIE base *srebh- "to suck, absorb" (cf. Arm. arbi "I drank;" Gk. rhopheo "to gulp down;" Lith. srebiu "to drink greedily").

Šamidan, from šam, variant of šâm, as in âšâm, âšâmidan "to drink, to sip;" Av. šam- "to drink, sip, swallow;" Skt. cam, camati "to sip, dirink, lick up, absorb."

The process of sorbing. The state of being sorbed. → absorption; → adsorption.

Verbal noun of → sorb

The interval after which the heliacal rising of the star Sirius occurs at the same time of the year. It is a period of 1,460 Sothic years.

From Fr. sothique, from Gk. Sothis, an Egyptian name of Sirius; → period.

Tištari, of or pertaining to Tištar→ serius; dowré, → period.

The Egyptian year of 365 days and 6 hours, as distinguished from them Egyptian vague year, which contained 365 days.

From Fr. sothique, from Gk. Sothis, an Egyptian name of Sirius; → year.

Tištari, of or pertaining to Tištar→ serius; sâl, → year.