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

→ fibula.

M.E., from M.Du. or M.L.G. splinte, splente "thin piece of iron," related to M.Du. splinte "splint," probably literally "thin piece cut off."

→ fibula.

The hard nonmetallic mineral or group of consolidated minerals either in mass or in a fragment of pebble or larger size. See also → rock.

O.E. stan; cf. O.N. steinn, Dan. steen, O.H.G., Ger. Stein; from PIE *stai- "stone," also "to thicken, stiffen" (cf. Skt. styayate "curdles, becomes hard;" Av. stay- "heap;" Gk. stear "fat, tallow," stia, stion "pebble").

Sang "stone, rock;" Mid.Pers. sang; O.Pers. aθanga-; Av. asenga- "stone;" PIE *aken-.

A prehistoric period during which the main material used to make tools and weapons was stone. The Stone Age is usually divided into three separate periods (Paleolithic Period, Mesolithic Period, and Neolithic Period) based on the degree of sophistication in the fashioning and use of tools. The Paleolithic time period is by far the longest, beginning some two million years ago and ending around 10,000 BC to coincide with the end of the last ice age (Pleistocene epoch).

→ stone; → age.

A line connecting the dust grains in a comet tail that left the nucleus at the same time. → syndyne.

From L. synchronus "simultaneous," from Gk. synchronos "happening at the same time," from → syn- "together" + khronos "time."

Hamzamân, from ham-, → syn- "together" + zamân, → time.

A jointed ring placed at the upper end of a → planispheric astrolabe astrolabe. By slipping one's thumb into the ring, one raises the instrument so that its weight and symmetrical design keeps it perpendicular to the ground (online museo galileo, VirtualMuseum).

From L. thronus, from Gk. thronos "elevated seat, chair, throne," from PIE root *dher- "to hold firmly, support;" cf. L. firmus "firm, steadfast, strong, stable," Skt. dharma- "statute, law;" Pers. dâr-, dâštan "to have, to possess," → property.

Korsi "throne, chair, seat," from Ar. kursī.

Any of the 24 zones on the Earth surface delimited by → meridians at approximately 15° intervals. In each time zone a common standard time is used, and the time is one hour earlier than the zone immediately to the east.

→ time; → zone.

A musical sound of definite pitch, consisting of several relatively simple constituents called partial tones, the lowest of which is called the fundamental tone and the others harmonics or overtones.

M.E., from O.Fr. ton, from L. tonus "a sound, tone, accent," literally "stretching," from Gk. tonos "vocal pitch, raising of voice," related to teinein "to stretch," cognate with Pers. tanidan "to spin, weave," → tension.

Ton, loan from Fr., as above.

The part of the Earth's surface between the tropics of Cancer and Capricorn

→ torrid; → zone.

An device consisting of four → resistances in series, used to determine the value of an unknown electrical resistance when the other three resistances are known.

Named after Charles Wheatstone (1802-1875), British physicist, who extensively used the circuit (1843) but was not its inventor. Such an arrangement of four resistances was first used by Samuel Hunter Christie (1784-1865) in 1833; → bridge.

One of several regions of the stellar interior where increased → opacity can provide the necessary → valve mechanism to drive → stellar pulsations. Also called → partial ionization zone.

Named after the Russian astronomer Sergei A. Zhevakin (1916-2001), who identified these zone in the 1950s; → mechanism.

The portion of the surface of a sphere included between two parallel planes.

From L. zona "geographical belt, celestial zone," from Gk. zone "a belt," related to zonnynai "to gird," from PIE base *yes- "to gird, girdle;" cognate with Pers. parhun "circle," as below.

Zonâr most probably loan from from Gk., as above; it is related to Pers. parhun "circle," ultimately from Proto-Iranian *pari-iâhana- "girdle, belt," from pari-, variant pirâ-, → circum-, + iâhana- "to girdle," cf. Av. yâh- "to girdle." The Pers. pirâhan "shirt" is a variant of parhun.

The region on the sky covered by the plane of the → Milky Way. It is characterized by an apparent absence of galaxies, due to the obscuring effect of → interstellar dust in the → Galactic plane.

→ zone; → avoidance.