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

1) The range of frequencies or wavelengths over which radiations are absorbed or emitted in a transition between a specific pair of atomic energy levels. The full width is determined between half-power points of the line.
2) In a laser, the range of frequencies over which most of the beam energy is distributed.

→ line; → width.

One of several → input or → output variables of a → fuzzy logic system whose values are → words or → sentences from a natural language, instead of numerical values.

→ linguistic; → variable.

The study of the structure and evolution of → language, including → phonetics, → morphology, syntax, semantics.

From linguistic, from linguistic, from linguist, from L. lingua, → language, + → ics.

Zabânik, from zabân, → language, + -ik, → -ics. Zabânšenâsi, from zabân + šenâsi, → -logy.

1) General: Anything serving to connect one part or thing with another; a bond or tie.
2) A direct connection in a hypertext document to the Internet address (URL) of another document.

From M.E. link(e), of Scandinavian origin; akin to O.Dan. lænkia "chain;" Old Norse hlekkr "chain;" Ger. Gelenk "joint."

Peyvand "join, union," from peyvandidan, peyvastan "to join, connect;" Mid.Pers. peywand, peywastan "connection, offspring; to join, connect, attach," from *pati-basta-, from suffix pati- (Mid.Pers. pât-,from O.Pers. paity "agaist, back, opposite to, toward, face to face, in front of," Av. paiti, akin to Skt. práti "toward, against, again, back, in return, opposite," Pali pati-, Gk. proti, pros "face to face with, toward, in addition to, near;" PIE *proti) + basta- "tied, shut" (Av./O.Pers. band- "to bind, fetter," banda- "band, tie," Skt. bandh- "to bind, tie, fasten," PIE *bhendh- "to bind," cf. Ger. binden, E. bind), cf. Skt. prati-bandh- "to tie."

1) General: An act or mode of linking; the fact of being linked.
2) Physics: The amount of magnetic flux passing through a coil of wire or other electric circuit.

From → link + -age a suffix of abstract nouns from O.Fr.

From ham-, → com-, + peyvand, → link, + noun suffix -y.

A large, usually tawny-yellow cat, Panthera leo, native to Africa and southern Asia, having a tufted tail and, in the male, a large mane (dictionary.com).

M.E., from O.Fr., variant of leon, from L. leon- (stem of leo), from Gk. leon.

Mid.Pers. šagr "lion;" cf. Parth. šarg; Sogd. šarγu "lion;" its O.Pers. and Av. forms are not extant. Šir may be cognate with Skt. kēsarin- "lion; literally maned," from kēsar- "mane;" PIE *kaisar- "mane; hairs." If so, šir could be related to PIE *kaisaraka-, provided that the the initial *kai- is dropped and *saraka- has transformed in *sarg, šarg, šir.

A key theorem in statistical mechanics of classical systems which states that the motion of phase-space points defined by Hamilton's equations conserves phase-space volume.

After Joseph Liouville (1809-1882), a French mathematician; → theorem.

1) The act or process of liquefying or making liquid.
2) The state of being liquefied.

→ liquefy; → -tion.

1) To reduce to a liquid state.
2) To become liquid.

M.E. lyquefyen, from O.Fr. liquefier, from L. liquefacere "make → liquid, melt," from liquere "be fluid" + facere "to make," → -fy.

The state of matter in which a substance exhibits a characteristic readiness to flow, little or no tendency to disperse, and relatively high incompressibility.

O.Fr. liquide, from L. liquidus "fluid, liquid, moist," from liquere "be fluid," related to liqui "to melt, flow."

Âvé, from âv, variant of âb "→ water" + nuance suffix -e.
Âbgun literally "resembling water," from âb "water," + gun "resembling; manner, fashion; color" (Mid.Pers. gônak "kind, species;" Av. gaona- "color").

A type of material that possesses less geometrical regularity or order than normal solid crystals, and whose order varies in response to alterations in temperature, electric field, and other quantities.

→ liquid; → crystal.

The state of helium (⁴He) below its boiling point of 4.2 K. Its normal form is called → helium I, but converts into superfluid → helium II below 2.17 K (→ lambda point). Liquid helium is colorless and transparent so that it is impossible to see the surface of the liquid with the naked eye. Helium was first liquefied in 1911 by the Dutch physicist Heike Kamerlingh Onnes (1853-1936), Physics Nobel Prize 1913.

→ liquid; → helium.

A mirror composed of liquid, taking advantage of the parabolic shape of a spinning liquid and the fact that the mirror's focal length can be adjusted by altering the velocity at which the liquid's container spins.

→ liquid; → mirror.

Water in a state that is neither ice nor vapor.

→ liquid; → water.

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

From L. liquidus, → liquid.

An → ESA spacecraft that was launched on December 3, 2015 to test technologies needed for the Evolved Laser Interferometer Space Antenna (eLISA), an ESA → gravitational wave observatory planned to be launched in 2034. LISA Pathfinder paves the way for future missions by testing in flight the very concept of gravitational wave detection.

LISA, short for → Laser Interferometer Space Antenna; → pathfinder.

A curve traced out by a point which is oscillating simultaneously in two mutually perpendicular directions. In general, the amplitude and frequency may be different in the two directions, and the two oscillations may have an arbitrary initial phase difference. The simplest pattern is a straight line, being obtained from two oscillations of equal frequency in phase with each other. The patterns can become very involved if the ratio of the frequencies is not a simple one.

After the French physicist Jules Antoine Lissajous (1822-1880), who first demonstrated such curves (Comptes-Rendus, 1857, 44, 727); → figure.

Xam, → curve.

A quasi-periodic path resembling a → Lissajous figure around the L1 or L2 → Lagrangian points of a two-body system. Lissajous orbits, resulting from a combination of planar and vertical components, are used by certain space telescopes (such as → WMAP, → Planck Satellite, and → Herschel Satellite) that are required to be in a stable position relative to the Earth and Sun while making long-term observations.

→ Lissajous figure; → orbit.

1a) A series of names or other items written or printed together in a meaningful grouping or sequence so as to constitute a record.
1b) Computers: A series of records in a file.
2) To set down together in a list; make a list of (Dictionary.com).

From M.E. liste "border, edging, stripe," from O.Fr. liste "border, band, row," also "strip of paper," or from O.It. lista "border, strip of paper, list," both from Germanic sources (compare O.H.G. lista "strip, border, list," O.Norse lista "border."

List, loan from Fr. liste, as above.

1) A list; the act of compiling a list; something listed.
2) Computers: A display or printed list of lines in a program or digital data.

→ list; → -ing.