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

The long span of time from the end of the formation of Earth during which our planet underwent its major transformations.

→ geologic; → time.

The vertical and horizontal transport of water in all its states between the earth, the atmosphere, and the seas; often called the water cycle.

Hydrologic, pertaining to → hydrology; → cycle.

1) The science that investigates the principles governing correct or reliable inference.
2) The system or principles of reasoning applicable to any branch of knowledge or study.
3) A particular method of reasoning or argumentation.

M.E. logik; O.Fr. logique, from L. (ars) logica, from Gk. logike (techne) "reasoning (art)," from feminine of logikos "pertaining to speaking or reasoning," from logos "reason, idea, word."

Guyik, from guy- present stem of goftan "to say, speak, relate, tell; to compose a poem," from Mid.Pers. guftan "to say, tell, utter;" O.Pers. gaub- "to say" + -ik, → -ic.
Cemguyik, from Mid.Pers. cimgôwâgih "logic," from cim "cause, reason, meaning" (Proto-Iranian *cahmāt "what for;" cf. Skt. kasmāt "why, where from," kim "what") + gôwâgih Mod.Pers. guyi, as above.

A diagram that uses special symbols called logic symbols to represent the detailed functioning of electronic logic circuits. The symbols do not represent the type of electronics used, but only their functions.

→ logic; → diagram.

1) According to or agreeing with the principles of logic.
2) Reasoning in accordance with the principles of logic, as a person or the mind.
3) Of or pertaining to logic (Dictionary.com).

→ logic; → -al.

A symbol that can be combined with one or more → sentences in order to form a new sentence. For example "and" (∧), "or" (∨) "not" (¬), "if-then" (→), and "iff" (⇔).

→ logical; → connective.

Describing two → compound propositions → if and only if they have the same → truth table.

→ logical; → equivalent.

Evaluation or measurement of one or more meteorological elements.

Meteorological, of or pertaining to → meteorology; → observation.

A scientific establishment dedicated to making precise and detailed meteorological observations and to studying and forecasting atmospheric phenomena by means of special equipments.

Meteorological, of or pertaining to → meteorology; → observatory.

Same as → Milne Universe.

→ Milne Universe; → cosmological; → model.

Of or relating to → morphology. Same as morphological

→ morphology; → -ic.

Of or relating to → morphology. Same as morphological

→ morphologic; → -al.

A classification scheme of galaxies based on their apparent shape. → Hubble classification.

→ morphological; → classification.

The → assumption, adopted by the → steady-state theory, that all observers, everywhere at all times, would view the same large-scale distribution of matter in the → Universe in all regions and in every direction. In contrast to the → cosmological principle, the perfect cosmological principle adds the assumption that the Universe does not change with time on the large scale.

→ perfect; → cosmological; → principle.

A system of logic with more than two → truth values, as opposed to → classical logic. A polyvalent logic may have a continuous scale of values with → true and → false as limiting → extremes.

→ polyvalent; → logic.

The generic term for systems of → formal logic like → first-order logic and → second-order logic. Predicate logic contains → variables which can be quantified (→ quantify, → quantification).

→ predicate; → logic.

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 n extension of → first-order logic that quantifies not only → variables that range over → individuals, but also quantifies over → relations.

→ second; → order; → predicate; → logic.

Same as → propositional logic.

→ sentential; → logic.

A modern development of → formal logic based on a system of → symbols and → axiomatics in accordance with precise rules. It uses a formalized → artificial language to avoid the ambiguities and logical inadequacies of → natural languages. Symbolic logics are → polyvalent when they admit → truth values other than → true and → false.

→ symbolic; → logic.