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

Reference from one part or element of a book or data catalog to something in another for further information.

→ cross; → reference.

A set of axes to which positions and motions in a system can be referred.

→ frame; → reference.

Same as → inertial reference frame.

→ Galilean; → reference; → frame.

A → reference frame or coordinate system in which there are no accelerations, only zero or uniform motion in a straight line. According to the special theory of relativity, it is impossible to distinguish between such frames by means of any internal measurement.

→ inertial; → reference; → frame.

1) Act of → preferring.
2) That which is preferred.

→ prefer; → -ence.

1) An act or instance of referring.
2) A book, article, or passage to which one is directed.

Verbal noun of → refer.

A mathematically defined surface that approximates the Earth's shape, which is basically a sphere "flattened" at its poles. The length of one of the axes at the Equator is chosen so that the ellipsoid coincides at this latitude with the mean sea level. It is the first-order definition of the non-spherical shape of the Earth as an ellipsoid of revolution. To first order, it accounts for over 90% of the → geoid.

→ reference; → ellipsoid.

A set of axes to which positions and motions in a system can be referred. Same as → frame of reference.

→ reference; → frame.

An astronomical source in a field used as a reference for the detection of another object, astrometry, etc.

→ reference; → source.