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

1) The act or an instance of expressing.
2) Math.: A statement using mathematical quantities such as → scalars, → variables, → parameters, → functions, and → sets, as well as → relational and → logical  → operators such as → equality, → conjunction, → existence, → union, etc. (Steven. G. Krantz, ed., Dictionary of Algebra, Arithmetic, and Trigonometry, 2001).

→ express; → -tion.

Same as → degeneracy pressure.

→ fermi; → pressure.

The term ρgz in the → Bernoulli equation. It is not pressure in a real sense, because its value depends on the reference level selected.

→ hydrostatic; → pressure.

1) To press, to apply with pressure, especially to leave a mark.
2) To produce a profound effect upon the mind.

→ in-; → press.

1) A strong effect produced on the intellect, feelings, conscience, etc.
2) The first and immediate effect of an experience or perception upon the mind (dictionary.com).

→ press + -ion variant of → -tion.

Capable of being impressed; easily impressed.

→ impress; → -able.

1) A style of painting developed in the last third of the 19th century, characterized chiefly by short brush strokes of bright colors in immediate juxtaposition to represent the effect of light on objects.
2) A manner of painting in which the forms, colors, or tones of an object are lightly and rapidly indicated.
3) A manner of sculpture in which volumes are partially modeled and surfaces roughened to reflect light unevenly (Dictionary.com).

→ impression; → -ism.

Having the power to impress, to raise admiration, awe, respect, etc.

→ impress; → -ive.

A flow whose volume or density does not change under pressure, and therefore its density is a constant. In other words, an ideal flow in which the → divergence of velocity is zero. → compressible flow.

→ incompressible, from → in "not" + → compressible; → flow.

The pressure exerted by a magnetic field on the material that contains the field.

→ magnetic; → pressure.

A kind of pressure that contrarily to ordinary pressure pushes inward. In contrast with the → Newtonian mechanics, in → general relativity there are situations in which pressure can be negative. Positive pressure gives rise to attractive gravity, whereas negative pressure creates → repulsive gravity.

→ negative; → pressure.

To burden with cruel or unjust impositions or restraints; subject to a burdensome or harsh exercise of authority or power (Dictionary.com).

M.E. oppressen, from O.Fr. opresser "oppress, torment, smother," from M.L. oppressare, from L. opprimere "press against, press together, press down; subdue, prosecute relentlessly," from op variant of ob "against" + premere "to press, hold fast."

Infinitive from setam, → oppression.

1) The exercise of authority or power in a burdensome, cruel, or unjust manner.
2) An act or instance of oppressing or subjecting to cruel or unjust impositions or restraints.
3) The state of being oppressed (Dictionary.com).

M.E. oppressioun, from O.Fr. opresser "oppress; torment," from M.L. oppressare, from L. opprimere "press against, press down;" from op, variant of ob "against" + premere "to press, hold fast."

Setam, from Mid.Pers. sthmbk / stambag / "oppressive; obstinate," related to sitabr "strong, firm," staft "hard; firm, strong; fierce," Pers. seft "firm, hard, tight;" sitanbah "strong, robust, bold;" Av. aša.stəmbana- "having the support/firmness of aša;" Lith stembti "to oppose;" Gk. astemphes "unshakable."

The hydrostatic pressure produced on the surface of a partially permeable membrane by osmosis.

→ osmotic; → pressure.

A mathematical analysis, based on → self-similarity, used to predict the → mass function of spherically collapsing → dark matter halos. The formalism assumes that the fraction of mass in halos more massive than M is related to the fraction of the volume in which the smoothed initial density field is above some threshold δ_cρ, where ρ is the average density of the Universe, with the volume encompassing a mass larger than M. A variety of smoothing → window functions and thresholds have been argued, but the most common is a top-hat window in real space and δ_c≅ 1.69. The Press-Schechter formalism provides a relatively good fit to the results of numerical simulations in cold dark matter theories.

First described by William H. Press and Paul Schechter's paper (1974, ApJ 187, 425); → formalism.

The force per unit area.

M.E., from O.Fr. pressure, from L. pressura "action of pressing," from pressus, p.p. of premere "to press, compress."

Fešâr "squeezing, constriction, compression," verb fešordan, fešârdan "to press, squeeze;" phonetic variants Lori xošâr, Aftari xešâr, Qazvini, Qomi xošâl; cf. Khotanese ssarr- "to exhilarate;" loaned in Arm. ôšarak, in Ar. afšaraj "juice."

A broadening of spectral lines caused mainly by the stellar atmospheric density and the surface gravity of the star. The line strength of a spectral line depends on the number of atoms in the star's atmosphere capable of absorbing the wavelength in question. For a given temperature, the more atoms there are, the stronger and broader the spectral line appears. Denser stars with higher surface gravity will exhibit greater pressure broadening of spectral lines.

→ pressure; → broadening.

The pressure difference between two adjacent regions of a fluid that results in a force being exerted from the high pressure region toward the low pressure region.

→ pressure; → gradient.

A force resulting from → pressure gradient that is directed from high to low pressure.

→ pressure; → gradient; → force.

A physical state of dense matter in which the electrostatic field of one atom should influence a neighboring atom and hence disturb atomic levels. In extreme case, such as white dwarfs, electron clouds practically rub and electrons are ionized off the parent atoms.

→ pressure; → ionization.