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

Being in or characterized by proportion.
Math.: Of two quantities, having the same or a constant ratio or relation.

→ proportion + → -al.

A device in which an electronic detection system receives pulses that are proportional to the number of ions formed in a gas-filled tube by ionizing radiation.

→ proportional; → counter.

Math.: A relationship bewteen two quantities such that if one quantity changes the other changes in the same proportion; denoted as y ∝ x.

→ proportional + → -ity.

Math.: A → constant that converts a proportionality into an → equation. Thus the proportionality constant k converts the proportionality y ∝ x into the equation y = kx.

→ proportionality + → constant.

1) The act of offering or suggesting something to be considered, accepted, adopted, or done.
2) A plan or scheme proposed.
3) Logic: A statement in which something is affirmed or denied, so that it can therefore be significantly characterized as either true or false.
4) Math.: A formal statement of either a truth to be demonstrated or an operation to be performed; a theorem or a problem (Dictionary.com).

Verbal noun of → propose.

Logic: Of, relating to, or in the form of a → proposition.

→ proposition; → -al.

Logic: A → propositional symbol that represents a → specific → proposition.

→ propositional; → constant.

A branch of logic that deals with the → truth values of logical statements (→ sentences, → propositions) and uses → logical connectives to build more complex → expressions. The distinctive feature of propositional logic is that it does not deal with logical relationships and properties that involve the parts of a statement smaller than the simple statements making it up. The propositions are evaluated as → true or → false. A more expressive system is provided by the → first-order logic.

→ proposition; → -al; → logic.

An upper case letter, e.g. "A," "B," "C," etc. representing a → proposition. Propositional symbols are divisible into two sorts: → propositional constants and → propositional variables.

→ propositional; → symbol.

Logic: A → propositional symbol that represents any → proposition whatsoever.

→ propositional; → variable.

The act or process of propelling. The state of being propelled.

Verbal noun from → propel.

1) The act of protesting.
2) Formal expression or declaration of objection, dissent, or disapproval (Dictionary.com).

→ protest; → -tion.

A → thermonuclear reaction in which two protons collide at very high velocities and combine to form a → deuterium. See also → proton-proton chain.

→ proton; → reaction.

1) The act of provoking.
2) Something that → incites, → instigates, angers, or irritates (Dictionary.com).

Verbal noun of → provoke.

The collective opinion of many people on some issue, problem, etc., especially as a guide to action, decision, or the like (Dictionary.com).

→ public; → opinion.

1) The act of publishing a book, periodical, map, piece of music, engraving, or the like.
2) The act of bringing before the public; announcement.
3) The state or fact of being published (Dictionary.com).

Verbal noun of → publish.

The act of pulsating; beating or throbbing; vibration or undulation. → stellar pulsation.

Verbal noun of → pulse.

The way in which pulsations occur in a star due to the fact that stars act as resonant cavities, as studied in → asteroseismology. A star may pulsate either with approximately spherical symmetry (radial pulsation), or as a series of waves running across the surface (non-radial pulsation). Pulsation may occur in a single mode or in multiple modes, depending on the type of star. Three different modes of pulsations have been detected through the → helioseismology of the → Sun: → p mode, → g mode, and → f mode, generated by acoustic, gravity, and surface gravity waves respectively. Also called → oscillation mode.

→ pulsation; → mode.

Of or pertaining to → pulsation. → pulsational instability; → pulsational pair-instability supernova.

→ pulsation; → -al

A term used to describe irregularly spaced, fine-scale structure in optically thick rings. The process relies on a combination of viscosity and self-gravity of ring material to produce this fine structure. Also known as overstability (Ellis et al., 2007, Planetary Ring Systems, Springer).

→ pulsational; → instability.