An Etymological Dictionary of Astronomy and Astrophysics
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A bright, narrow stream of particles traveling through the Sun's corona, visible in images taken with a coronagraph or during a total solar eclipse. Coronal streamers represent the most outwardly extended structures in the solar corona and result from the interaction between the solar slow wind and the large-scale magnetic field. → helmet streamer.

→ coronal; → streamer.

1) With or in the direction of the current of a stream. → upstream.
2) Of or pertaining to the latter part of a process or system.

→ down; → stream.

Forud, → incidence; water, → water.

A group of stars pervading the Solar neighbourhood and travelling in the → Galaxy with a similar spatial velocity, such as the → Ursa Major star cluster, The term dynamical stream is more appropriate than the traditional term supercluster since it involves stars of di fferent ages, not born at the same place nor at the same time. A possible explanation for the presence of young groups in the same area as those streams is that they have been put there by the → spiral wave associated with their formation place, while kinematics of the older stars of the sample have also been disturbed by the same wave. The seemingly peculiar chemical composition of the Hyades-Pleiades stream suggests that this stream originates from a specific galactocentric distance and that it was perturbed by a spiral wave at a certain moment and radially pushed by the wave in the solar neighbourhood. This would explain why this stream is composed of stars sharing a common metallicity but not a common age (Famaey et al. 2005, A&A 430, 165).

→ dynamical; → stream.

A large-scale → coronal feature with apparent → cusp, seen during a → solar eclipse. They usually arise from → sunspots and → active regions, so at the base of a helmet streamer one will often find a → prominence.  They form magnetic loops that connect the sunspots and suspend material above the surface of the Sun.  The magnetic field lines trap the material to form the streamers. The action of the → solar wind is at the origin of the peak feature.

→ helmet; → streamer.

A systematic trend in the motion of some → Galactic halo→ old stars thought to be a relic of the → merging of a dwarf satellite galaxy devoured by our Milky Way. Using kinematic data from the → Hipparcos satellite, Helmi et al. (1999, Nature 402, 53) found two halo star streams which share a common progenitor: a single coherent object disrupted during or soon after the Milky Way's formation, and which probably resembled the Fornax and Sagittarius dwarf spheroidal galaxies.

See also Helmi & White 1999, MNRAS 307, 495; → stream.

Meteo.: An area of relatively strong winds that are concentrated in a narrow band in the upper troposphere of the middle latitudes and subtropical regions of the Northern and Southern Hemispheres.

→ jet; → stream.

A thin trail of gas stretching from the → Magellanic System toward our own Galaxy over about 150° on the sky, corresponding to hundreds of thousands of light-years. This gas consists primarily of → neutral hydrogen and is thought to have originated from the Large and Small Magellanic Clouds as a result of tidal interactions with the Milky Way. See, e.g., Fox et al. 2013, arxiv/1304.4240, and references therein.

→ Magellanic; → stream.

The meteoroids distributed all along an → orbit and diffused somewhat around it.

→ meteoroid; → stream.

1) (n.) A general term for any river, brook, rivulet or course of running water.
A steady flow of a fluid, small solid particles, or radiant energy. → Magellanic stream. Related concepts: → current (jarayân = جریان); → flow (tacân = تچان).
2) (v.) To move or proceed continuously like a flowing stream.

O.E. stream "a course of water;" cf. O.S. strom, O.N. straumr, Dan. strøm, Swed. ström, Norw. straum, Du. stroom, O.H.G. stroum, Ger. Strom "current, river," from PIE base *sreu- "to flow;" cf. Pers. rud, from Mid.Pers. rôd "river;" O.Pers. rautah- "river;" Skt. srotas- "river," sru- "to flow;" Pali sota- "stream, flood;" Gk. rhoos "a stream, a flowing," from rhein "to flow."

1) Râbé, from dialectal Gilaki râbé "flowing of water or liquid," Semnâni rové "a stream of water flowing beyond control," Pers. colloquial râ (in râ gereftan "to overflow, flow beyond control"); probably from PIE base *rei- "to flow;" cf. Skt. ray- "to flow, run," raya- "stream;" L. rivus "stream, brook;" O.C.S. reka "river;" M.Ir. rian "river, way;" Goth. rinnan "run, flow," rinno "brook;" M.L.G. ride "brook;" O.E. riþ "stream."
2) Râbidan infinitive of râbé.

Hydrology: A steady current in a stream or river.
Oceanography: A deep, narrow, well-defined fast-moving ocean current.

→ stream; → current.

A → stream tube with a small cross section so that the variation of velocity over it is negligible.

→ stream; → filament.

A pipe-shaped volume obtained by drawing → streamlines through every point of a closed curve in the fluid. Since the stream tube is bounded on all sides by streamlines and since, by definition, there can be no velocity across a streamline, no fluid may enter or leave a stream tube, except through its ends. See also → stream filament.

→ stream; → tube.

Any long, narrow piece or thing, as a spray of a plant or a strip of cloud; something that streams. → coronal streamer; → helmet streamer

M.E. stremer, from → stream + -er.

Derafšak, from derafš "flag, banner;" Mid.Pers. drafš "banner;" Av. drafša- "banner;" cf. Skt. drapsá- "flag, banner; drop, spark;" also Fr. drapeau; It. drappo "flag;" Lith. drapana "dress."

1) Fluid mechanics: Any process or instance of flowing.
2) Computer science: A condition of a terminal or modem that has locked into a constant carrier signal, thus preventing the normal flow of data.

Verbal noun of → stream.

An imaginary continuous curve drawn in a fluid so that the tangent at every point of it at any instant of time coincides with the direction of the motion of the fluid at that point. The component of velocity at right angles to the streamline is always zero. If a number of streamlines is considered at a particular instant, the pattern they form gives a good indication of the flow then occurring. Same as → flow line. See also → path line, → stream tube.

→ stream; → line.

1) Toward or in the higher part of a stream; against the current. → downstream
2) Directed upstream; situated upstream.

→ up; → stream.

Farâz, → height; water, → water.