rapidly oscillating Ap star
Fr.: étoile Ap à oscillation rapide
A chemically peculiar star characterized by the presence of high-frequency non-radial oscillations, with periods that range between about 4 and 16 min. These variations have periods from about 5 to 20 minutes and low amplitudes (B < 10 mmag). They are consistent with acoustic (→ p mode) pulsations of low degree and high radial overtone.
A part of a river where the current runs very swiftly. See also → torrent.
perz, kamyâb (#)
Not occurring very often; not found in large numbers.
M.E., from O.Fr. rere "sparse" from L. rarus "thinly sown; not thick; having intervals between."
Perz, in several Iranian languages and dialects "little, few, small, minute
part of any thing" (Khonsâri: perz, Qatrâni: perzema,
Birjandi: porzu, Farâmarzâni: pesk, Kurd petik,
Tabari: perik "minute quantity, particle"); maybe ultimately from
Proto-Ir. *paraka- "small part," → part.
rare earth element
bonpâr-e xâki-ye kamyâb, xâk-e kamyâb
Fr.: terre rare
Any of the group of metallic → chemical elements with → atomic numbers between 57 and 71 inclusive. The name is an inappropriate terminology, since they are neither rare nor earth; preferred name → lanthanide.
gâz-e kamyâb (#)
Fr.: gaz rare
Another name for → inert gas.
M.E., from O.Fr. rere "sparse," from L. rarus "loose, wide apart, thin, infrequent;" &rar; gas.
Kamyâb "rare, difficult to find," from kam "little, few; deficient, wanting; scarce" (Mid.Pers. kam "little, small, few," O.Pers./Av. kamna- "small, few"); + yâb present stem of yâftanyâftan, yâbidan "to find, discover; to obtain, acquire" (Mid.Pers. ayâftan, ayâpênitan "to reach, attain;" Manichean Mid.Pers. 'y'b "to attain;" Parthian, Sogdian (+ *pati-) pty'b "to reach, obtain;" Av. ap- "to reach, overtake," apayeiti "achieved, reached;" Skt. âp- "to reach, gain," âpnoti "reaches, gains;" Gk. hapto, haptomai "to touch, cling to, adhere to;" L. apiscor "touch, reach;" PIE base *ap- "to take, reach").
The state of being rarefied, less dense.
M.E. rarefien, from M.Fr. rarefier, from L. rarefacere "make rare," from rarus "loose, wide apart, thin, infrequent."
Verbal noun from âlar present stem of âlaridan→ rarefy + -š, a suffix.
Fr.: onde de raréfaction
A pressure wave in a fluid generated by rarefaction. It travels in the opposite direction to that of a shock wave in the medium.
Fr.: gaz raréfié
A gas whose pressure is much less than a reference pressure.
M.E. rarefien, from M.Fr. rarefier, from rare, combining form of rarus "loose, wide apart, thin, infrequent."
Alaridan, infinitive of âlar, from intensive/nuance prefix â- + lar "thin, meagre" (Dehxodâ), Lori, Laki larr, larrek "thin cow or sheep," Kurd. lerr "thin, lean," variants of laqar (Torbat-Heydariyé), lâqar "lean, meagre, slender; weak."
Rasalgethi (α Herculis)
The brightest star in the constellation → Hercules. It is a → red supergiant of type M5 (surface temperature about 3300 K) lying at a distance of 380 light-years. Rasalgethi is a variable star with a mean magnitude of V = 3.48. It has a fifth magnitude companion 5'' away. This secondary is itself a double that consists of a 4 solar-mass class G5 giant star with a temperature about that of the Sun and a 2.5 solar-mass F2 dwarf star (somewhat hotter than the Sun) in orbit around each other separated by 0.4 AU with a 52 day period.
Rasalgethi, from Ar. Ra's al-Jathi (
Rasalhague (α Ophiuchi)
The brightest star (V = 2.08) in the constellation → Ophiuchus. Rasalhague is a → giant star of type A5 lying 47 light-years from Earth. It has a faint, very close companion only 0''.5 away, 7 A.U., that orbits with a period of 8.7 years.
Rasalhague, from Ar. Ra's al-Hayyah (
The amount of change of some quantity during a time interval divided by the length of the time interval.
M.E. rate "monetary value," M.Fr. rate "price, value," from M.L. rata (pars) "fixed (amount)," from L. rata "fixed, settled," p.p. of reri "to reckon, think," → reason.
Nerx "rate, price, tariff."
Math.: The quotient of two quantities arrived at by dividing one by the other.
From L. ratio "reckoning, calculation," also "reason," from rat-,
p.p. stem of reri "to reckon, calculate," also "think," → reason.
Vâbar, on the model of Fr. rapport "bringing back," as above, from vâ- prefix meaning "back to the original place, again," → re-, + bar present stem of bordan "to carry, lead" (Mid.Pers. burdan, O.Pers./Av. bar- "to bear, carry," barəθre "to bear (infinitive)," Skt. bharati "he carries," Gk. pherein, L. fero "to carry;" PIE base *bher- "to carry").
1) râyani, râyanvâr; 2) xeradâné, xeradmandâné; 3) vâbari
1) Having or exercising the ability to → reason.
M.E. racional, from O.Fr. racionel, from L. rationalis "of or belonging to reason, reasonable," from ratio (genitive rationis) "reckoning, calculation, reason," from rat-, pp. stem of reri "to reckon, calculate; consider, think."
1) Râyani, of or pertaining to râyan, → reason.
Fr.: nombre rationnel
Any number that can be expressed as a ratio of two integers, providing the second number is not zero.
Fr.: raisonnement, exposé raisonné
1) The fundamental reason or reasons serving to account for something.
L. neuter of rationalis.
A philosophical doctrine that holds that → reason alone, unaided by experience, can arrive at basic truth regarding the world.
From → rational + -ism a Gk. suffix used in the formation of nouns denoting action or practice, state or condition, principles, doctrines, and so forth.
Râyan, → reason; xerad, → rational; bâvari, from bâvar "belief" (Mid.Pers. wâbar "beleif;" Proto-Iranian *uar- "to choose; to convince; to believe;" cf. Av. var- "to choose; to convince" varəna-, varana- "conviction, faith;" O.Pers. v(a)r- "to choose; to convince;" Skt. vr- "to choose," vara- "choosing").
Any of several large, corvine birds having lustrous, black plumage and a loud, harsh call, especially Corvus corax, of the New and Old Worlds (Dictionary.com).
M.E., from O.E. hræfn, hrefn; cf. O.N. hrafn, Dan. ravn, Du. raaf, O.H.G. hraban, Ger. Rabe "raven," O.E. hroc "rook," from PIE root *ker-, → crow.
Varâq, from Mid.Pers. varâγ "crow."
Fr.: données brutes
Data that are unprocessed or not yet subjected to analysis.
Raw, from M.E., from O.E. hreaw "uncooked, raw;" cf. M.Du. rau, O.H.G. hrawer, Ger. roh; PIE base *krowos "congealed, bloody" cf. Skt. kravis- "raw flesh," krura- "bloody, raw, hard;" Gk. kreas "flesh;" L. crudus "not cooked," cruor "thick blood;" Lith. kraujas, O.C.S. kruvi "blood;" → data.
Dâdehâ→ data; xâm "crude, uncooked;" Mid.Pers. xâm "crude, raw" (Khotanese hāma- "raw;" Ossetic xom "raw;" Pash. ôm "raw"); cf. Skt āmá- "raw, uncooked;" Gk. omos "raw, uncooked."
1) Any of the lines or streams in which light appears to radiate from a
luminous body. → light ray.
M.E. raie, raye, from O.Fr. rai "ray, spoke," from L. → radius "ray, spoke, staff, rod."
Partow, ultimately from Proto-Iranian *pari-tap- "to shine around, radiate away." The first component *pari- "around, about;" cf. Mod.Pers. par-, pirâ- "around, about," from Mid.Pers. pêrâ; O.Pers. pariy "around, about," Av. pairi "around, over," per- "to pass over, beyond;" Skt. pari; Gk. peri "around, about, beyond;" L. per "through;" PIE base *per- "through, across, beyond." The second component *tap- "to shine, radiate;" cf. Mod.Pers. tâbidan, variants tâftan "to shine," tafsidan "to become hot;" Mid.Pers. tâftan "to heat, burn, shine;" taftan "to become hot;" Parthian t'b "to shine;" Av. tāp-, taf- "to warm up, heat," tafsat "became hot," tāpaiieiti "to create warmth;" cf. Skt. tap- "; to heat, be/become hot; to spoil, injure, damage; to suffer," tapati "burns;" L. tepere "to be warm," tepidus "warm;" PIE base *tep- "to be warm."