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

1) To a double measure or degree.
2) In a double manner. → doubly convex, → doubly ionized, → doubly refracting crystal.

→ double; → -ly (; → twice).

Describing a → lens which is → convex on both sides.

→ doubly; → convex.

An atom that has lost two of its external electrons, for example O⁺⁺ ([O III]).

→ doubly; → ionized.

A → transparent → crystalline substance (such as calcite, quartz, and tourmaline) that is → anisotropic relative to the → speed of light. A ray incident normally on such crystals is broken up into two rays in traversing the crystal, → ordinary ray and → extraordinary ray.

→ doubly; → refracting; → crystal.