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

1) That conforms, especially to the shape of something.
2) Math.: Of, pertaining to, or specifying a mapping of a surface upon another surface so that all angles between intersecting curves remain unchanged.

→ con- + → form + → -al.

A mapping of an infinite → space-time onto a finite one that may make the far away parts of the former accessible to study. The technique invented by Penrose defines an equivalence class of → metrics, g_ab being equivalent to ĝ_ab = Ω²g_ab, where Ω is a positive scalar function of the space-time that modifies the distance scale making the asymptotics of the physical metric accessible to study.

→ conformal; → compactification.

A cosmological model developped by Roger Penrose and colleagues according which the Universe undergoes repeated cycles of expansion. Each cycle, referred to an aeon, starts from its own "→ big bang" and finally comes to a stage of accelerated expansion which continues indefinitely. There is no stage of contraction (to a "→ big crunch") in this model. Instead, each aeon of the universe, in a sense "forgets" how big it is, both at its big bang and in its very remote future where it becomes physically identical with the big bang of the next aeon, despite there being an infinite scale change involved, on passing from one aeon to the next. This model considers a conformal structure rather than a metric structure. Conformal structure may be viewed as family of metrics that are equivalent to one another via a scale change, which may vary from place to place. Thus, in conformal space-time geometry, there is not a particular metric g_ab, but an equivalence class of metrics where the metrics ğ_ab and g_ab are considered to be equivalent if there is a smooth positive scalar field Ω for which ğ_ab = Ω g_ab (R. Penrose, 2012, The Basic Ideas of Conformal Cyclic Cosmology).

→ conformal; → cyclic; → cosmology.

The study of the set of angle-preserving transformations on a space.

→ conformal; → geometry.

A continuous mapping u = f(x) of a domain D in an n-dimensional Euclidean space (n≥ 2) into the n-dimensional Euclidean space is called conformal at a point x₀∈ D if it has the properties of constancy of dilation and preservation of angles at this point.

→ conformal; → mapping.

1) To throw into confusion or disorder.
2) To treat or regard erroneously as identical; mix or associate by mistake (Dictionary.com).

M.E. conf(o)unden, from Anglo-Fr. confoundre, O.Fr. confondre "throw into disorder, crush, ruin," from L. confundere "to confuse," literally "to pour together, mix, mingle," from → com- + fundere "to pour"

Pašidan, from Tâti paši "confused, blend;" ultimately from Proto-Ir. *apa-šan-, from *šan- "to shake;" cf. Mid.Pers. pašân-, afšân- "to spread, scatter;" Pers. afšândan "to disperse;" Kurd. pašiv "messy, disordered," pašukân "to be agitated, distraught;" Gilaki voršin "messy, disordered;" see → chaos for other dialectal examples.

1) To make unclear or indistinct.
2) To fail to distinguish between; associate by mistake; confound (Dictionary.com).

Back formation from confused, M.E. confused, from O.fr. confus, from L. confusus, p.p. of confundere, → confound.

→ confound.

1) (Of a person) Unable to think clearly; perplexed.
2) Lacking order and so difficult to understand. Disordered.

Past participle of → confuse.

1) The act of confusing.
2) The state of being confused.
3) Disorder; upheaval; tumult; chaos (Dictionary.com).

Verbal noun of → confuse.

The → fluctuations of the → background  → sky brightness below which astronomical → sources cannot be → detected individually. The confusion limit is reached when the density of sources brighter than the → root mean square  → noise becomes high enough within the area of the resolution element.

→ confusion; → limit.

1) Anything composed of heterogeneous materials or elements.
2) Geology: A sedimentary rock made of rounded rock fragments (greater than two millimeters in diameter), such as pebbles, cobbles, and boulders, in a finer-grained matrix.

From L. conglomeratus, p.p. of conglomerare "to roll together," from → com- "together" + glomerare "to gather into a ball," from glomus (genitive glomeris) "a ball," globus "globe;" PIE *gel- "to make into a ball."

Hâgolemidan, from hâ- "together," → com-, + golem "glomus," → agglomerate.

1) The act of conglomerating; the state of being conglomerated.
2) a cohering mass; cluster (Dictionary.com).

Verbal noun of → conglomerate.

The quality or state of agreeing or corresponding. → congruent.

Noun form of → congruent.

1) Agreeing; accordant.
2) Math.: → congruent number.
3) Geometry: → congruent angles, → congruent circles, → congruent line segments, → congruent polygons, → congruent triangles.

Congruent "suitable, proper," from L. congruentem (nominative congruens) "agreeing, fit, suitable," p.p. of congruere, literally "to come together, agree, correspond with," from → com- "with" + a lost verb *gruere, *ruere "fall, rush."

Damsâz "agreeing, consenting, harmonious," maybe from hamsâz "unanimous," → compatible.

Two angles if they have the same measure. Congruent angles may lie in different orientations or positions.

→ congruent; → angle.

Two circles if they have the same size.

→ congruent; → circle.

Two line segments if they have the same length. They need not lie at the same angle or position on the plane.

→ congruent; → line; → segment.

Number theory: An → integer N if there exists a → right triangle with → rational sides so that the area of the triangle is N. For example, the number N = 6, because of the 3-4-5 triangle.

→ congruent; → number.

Polygons that have an equal number of sides, and all the corresponding sides and angles are congruent. However, they can be in a different location, rotated or flipped over.

→ congruent; → polygon.

Two triangles when all corresponding sides and interior angles have the same measure. The triangles will have the same shape and size, but one may be a mirror image of the other.

→ congruent; → triangle.