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

Turned into or covered with → ice. See also: → water ice.

Past participle of → freeze.

A member of a class of → pre-main sequence stars that experience dramatic changes in magnitude and → spectral type. During an outburst the luminosity of such an object can increase by several orders of magnitude on short time-scales (few months to few years). The phenomenon is explained by abrupt mass transfer from an → accretion disk to a young, low mass → T Tauri star (accretion rates 10^-4 to 10^-3 solar masses per year). → EX Lupi; → Z CMa.

F and U, alphabet letters; Orionis, → Orion; → object.

Completely filled; containing all that can be held; complete; entire; maximum.

O.E. full "completely, full," from P.Gmc. *fullaz (cf. O.Fris. ful, O.N. fullr, O.H.G. fol, Ger. voll), akin to Pers. por, as below.

Por "full;" Mid.Pers. purr "full;" O.Pers. paru- "much, many;" Av. parav-, pauru-, pouru-, from par- "to fill;" PIE base *pelu- "full," from *pel- "to be full;" cf. Skt. puru- "much, abundant;" Gk. polus "many," plethos "great number, multitude;" O.E. full.

Same as → apogee full Moon.

→ full; → micro-; → Moon.

1) The moon at → opposition, when it appears as a round disk to an observer on the Earth because the illuminated side is toward him.
2) The phase when the → age of the moon, measured from → new moon, is 14.5 days.

→ full; → moon.

Pormâh, from Mid.Pers. purrmâh, from Av. pərənô.manha- "full moon" (cf. Skt. pūrná-mās-); → full; → moon.

Same as → perigee full Moon.

→ full; → super-; → Moon.

The full width of a → profile (spectral line or a cross-cut in an image component) at half-maximum intensity.

→ full; → width; → half; → maximum.

Pahnâ, → width; nim, → half; bišiné, → maximum.

A mathematical rule between two sets which assigns to each element of the first exactly one element of the second, as the expression y = ax^b.

From M.Fr. fonction, from O.Fr. function, from L. functio (gen. functionis) "performance, execution," from functus, p.p. of fungor "to perform, execute."

Karyâ, from Av. kairya- "function;" cf. Mod.Pers. Laki karyâ "done," Awromâni kiriyây, kiria "to be done," from kar- "to do" (Mod.Pers. kar-, 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") + -ya suffix of verbal adjectives and nouns (e.g. išya- "desirable," jivya- "living, fresh," haiθya- "true," maidya- "middle," dadya- "grain"); cf. Skt. kāryá- "work, duty, performance."

1) Math.: Of, relating to, or affecting a function.
2) A → function that associates a → real number or → complex number to a function or a → set of functions. A functional can be considered as a function of a set of several infinite and continuous → variables.

→ function; → -al.

1) Being an original or primary source.
2) A basic principle, rule, law, or the like, that serves as the groundwork of a system.

L.L. fundamentalis "of the foundation," from L. fundamentum "foundation," from fundare "to found."

Bonyâdin, adj. of bonyâd "foundation, basis," from *bondâd (Mid.Pers. bune dâtak "foundation, basis"), from bon "basis; root; foundation; bottom" (Mid.Pers. bun "root; foundation; beginning," Av. būna- "base, depth," cf. Skt. bundha-, budhná- "base, bottom," Pali bunda- "root of tree") + dâd "given," from dâdan "to give" (Mid.Pers. dâdan "to give," O.Pers./Av. dā- "to give, grant, yield," dadāiti "he gives;" Skt. dadáti "he gives," Gk. didomi "I give," tithenai "to put, set, place;" L. dare "to give, offer;" Rus. delat "to do;" O.H.G. tuon, Ger. tun, O.E. don "to do").

A physical constant that cannot be expressed in terms of other constants of nature, such as the charge of the electron.

→ fundamental; → constant.

Same as the → fundamental interaction.

→ fundamental; → force.

The lowest frequency in a complex wave.

→ fundamental; → frequency.

Any of the four interactions in nature between bodies of matter and that are mediated by one or more particles. Also called the → fundamental force. In order of decreasing strength, the four fundamental interactions are the → strong interaction, the → electromagnetic interaction, the → weak interaction, and the → gravitational interaction.

→ fundamental; → interaction.

Same as → elementary particle.

→ fundamental; → particle.

A relatively bright star for which coordinates and proper motion have been determined to a very high degree of accuracy.

→ fundamental; → star.

1) To unite or blend into a whole, as if by melting together. Related terms: → coalesce; → merge; → unify.
2) To combine or blend by melting together; melt (Dictionary.com).

From L. fusus "poured, melt, cast," p.p. of fundere "to pour, melt."

1) Ividan, literally "to make (combine) into one entity," from iv, → one, + -idan infinitive suffix.
2) Godâxtan "to melt," from Mid.Pers. vitâxtan, vitâcitan "to melt," from Av. vi-taxti- "flowing away, melting," from vi- "apart, away from, out" (O.Pers. viy- "apart, away;" cf. Skt. vi- "apart, asunder, away, out;" L. vitare "to avoid, turn aside") + tak- "to run, to flow," taciāp- "flowing water," tacinti (3pl.pers.act.) "to flow," tacar- "course," tacan "current, streaming;" Mod.Pers. tâz-, tâxtan "to run; to hasten; to assault," tâzi "swift (greyhound)," tak "running, rush;" Mid.Pers. tâz-, tâxtan "to flow, to cause to walk," tc- "to flow, to walk," tag "running, attack," tâzig "swift, fast;" Khotanese ttajs- "to flow, to walk;" cf. Skt. tak- "to rush, to hurry," takti "runs;" O.Ir. tech- "to flow;" Lith. teketi "to walk, to flow;" O.C.S. tešti "to walk, to hurry;" Tokharian B cake "river;" PIE base *tek^w- "to run; to flow;" → flow.

1) The act or process of fusing; the state of being → fused; that which is fused; the result of fusing.
2) A → nuclear reaction between atomic nuclei (→ nucleus) as a result of which a heavier nucleus is formed and a large quantity of → nuclear energy is released. → proton-proton chain, → CNO cycle, → nucleosynthesis.
3) Change of the → state of a → substance from → solid to → liquid which occurs at a definite → temperature at a given applied → pressure. Same as melting.

From M.Fr. fusion, from L. fusionem, from fusus, p.p. of fundere "to pour, melt."

Verbal noun form of → fuse.

General: Time that is to be or come hereafter.
In a → space-time diagram, those events that could be influenced by a given element.

M.E. futur, from O.Fr., from L. futurus "about to be," irregular suppletive future participle of esse "to be."

Âyandé "future" agent noun/adjective of âmadan "to come, to occur, to become," from Mid.Pers. âmatan; O.Pers. gam- "to come; to go," Av. gam- "to come; to go," jamaiti "goes;" Proto-Iranian *āgmatani; Skt. gamati "goes;" Gk. bainein "to go, walk, step;" L. venire "to come;" Tocharian A käm- "to come;" O.H.G. queman "to come;" E. come; PIE root *gwem- "to go, come."

The set of all points in a → space-time diagram that are reached by signals travelling from a specified point at the speed of light.

→ future; → light; → cone.