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

In general, the process of repeatedly adding a quantity to itself a certain number of times, or any other process which has the same result.

Verbal noun of → multiply.

The sign used to indicate multiplication, either a times sign (×), a centered dot (·), or an asterisk. The multiplication sign was introduced by William Oughtred in 1631.

→ multiplication; → sign.

Involving → multiplication.

From multiplicate, → multiply, + → -ive.

The number which when used as the multiplier of another number leaves the second unchanged; one.

→ multiplicative; → identity.

The number which when used as a multiplier of another number (except 0) produces 1. For example (1/5) x 5 = 1; each of the numbers is the multiplicative inverse of the other.

→ multiplicative; → inverse.

1) The state of being multiple, made of several components.
2) In atomic and nuclear physics, the number of → levels into which the energy of an atom, molecule, or nucleus splits as a result of → Russell-Saunders coupling between → orbital angular momentum and → spin angular momentum. It is given by 2S+1, where S is the total electron → spin quantum number. The multiplicity of an energy level is indicated by a left superscript to the value of L, where L is the resultant electron orbital angular momentum of the individual electron orbital angular momenta.
3) In → statistical mechanics, the number of → microstates corresponding to a given → macrostate.

→ multiple; → -ity.

Arithmetic: A number by which another is multiplied. Physics: A device for intensifying some effect.

Agent noun of → multiply.

To make many or manifold; increase the number, quantity, etc., of.
Arithmetic: To find the product of by multiplication.

O.Fr. multiplier, from L. multiplicare "to increase," from multiplex (gen. multiplicis) "having many folds, many times as great in number," from multi- "many" + base of plicare "to lay, fold, twist."

Bastâyidan, from bastâ, → multiple, + -idan infinitive suffix.

An entity consisting of several poles.

→ multi-; → pole.

A variable used in → spherical harmonic expansions. Each spherical harmonic is characterized by its multipole index l: l = 0 for a → monopole, l = 1 for a → dipole, and so on. It is used in particular to describe the → cosmic microwave background anisotropy: ΔT/T₀ (θ,φ) = Σ a_lmY_lm(θ,φ), where θ and φ are the → spherical polar coordinates, Y_lm is the → spherical harmonic functions, and the sum runs over l = 1, 2, ..., ∞ and m = -l, ..., l, where the multipole index l corresponds to angular scales ≅ 180°/l.

→ multipole; → index.

The quantity that gives the electric potential field due to a distribution of charges, such as a → dipole, → quadrupole, → octupole, etc. A multipole moment usually involves powers of the distance to the origin, as well as some angular dependence.

→ multi-; → pole; → moment.

1) A great number.
2) A great number of people gathered together; crowd; throng.
3) The state or character of being many; numerousness.

M.E., from O.Fr. multitude and directly from L. multitudo "a great number, a crowd; the common people," from multus "many, much," → multi-, + suffix -tudo "-tude."

Basiné, from basin + superlative of bas "many, much," → multi-, + suffix -in + -é noun/nuance suffix (as bišiné, kaminé, etc.).

Statistics: Having more than one → variable.

→ multi-; → variate.

A → time series consisting of two or more → univariate time series which share the same time period. As an example, if we record wind velocity and wind direction at the same instant of time, we have a multi-variate time series, specifically a bivariate one.

→ multivariate; → time; → series.

A → hypothetical set of → multiple universes, including our → Universe, that together comprise all of physical reality.

Initially coined by William James (1895) "an alternative to universe meant to convey absence of order and unity." In modern cosmology coined from -verse in → universe, by replacing uni- with multi- to denote "multiple universes."

Gitigân, from giti, → universe, + -gân multiplicity suffix.

Same as → Charpak's detector.

→ multi-; → wire; → proportional; → chamber.

A short-lived → elementary particle with negative → electric charge, represented by the symbol μ^-. The muon was discovered in 1936 by Carl Anderson (1905-1991) in → cosmic rays. It shares several properties with the electron: it is a → lepton with the same charge and → spin as the electron. But it is heavier than the electron (105 MeV/c²), about 200 times more massive. The muon is instable and decays after 2.197 × 10^-6 s into → electron, → neutrino, and → antineutrino (μ^-→ e^- + ν_μ + anti ν_e) .

A shortening of mu meson, from mu the 12th letter of the Gk. alphabet, + → meson.

An → instrument used in → geophysics to determine the average → density of geological bodies by measuring the → attenuation produced by → rocks on the flux of → atmospheric muons. This density muon → radiography is or example used to study the physical conditions inside → volcanoes.

→ muon; → telescope.

Of, relating to, or resembling a wall.

From M.Fr. muraille, from L. muralia, neut. pl. o f muralis "of a wall," from murus "wall."

Divâri "of a wall," from divâr "wall," from Mid.Pers. dîvâr "wall;" related to Mid.Pers. bâr, var "enclosure, defences, fortress;" Mod.Pers. bâru "wall, rampart, fortification; fort; tower;" O.Pers. didā- "wall, stronghold, fortress;" Av. var- "castle," from var- "to cover, conceil;" Proto-Iranian *dida-vāra-; cf. Skt. dehī- "wall;" Gk. teikhos "wall;" E. dike, ditch.

An angle measuring device mounted on or built into a wall. For astronomical purposes, these walls were oriented so they lie precisely on a meridian.

→ mural; → instrument.