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

Insufficiently qualified for a particular job (OxfordDictionaries.com).

→ under-; → qualified.

The circumstance in which there are not enough pixels in a star's image. The number of pixels that make up a star's image is determined by the relationship between the telescope focal length, the physical size of the pixels, and the size of the star's image. With an undersampled image it is not possible to obtain accurate estimates of the star's image size or its position. Undersampling occurs when the atmospheric seeing conditions are exceptionally good and the pixel size not small enough.

→ under-; → sampling.

To perceive the meaning of.

M.E. understanden, understonden, O.E. understandan "comprehend, grasp the idea of," probably literally "to stand in the midst of," from → under- + standan "to stand," cognate with Pers. istâdan, → standard.

Fahmidan, from Ar. fahm + infinitive suffix -idan.

The ability to understand something; the → power of → abstract  → thought.

→ understand; → -ing.

1) Not definitely or authoritatively decided or settled.
2) Not known.

→ un-; → determined.

A type of meteorite in which the constituting materials (stone, glass, metal) are mixed together in a disorderly mass, in contrast to → differentiated meteorites.

→ un-; → differentiated meteorite.

A wave; the motion of waves.
A wavelike motion in any medium.

From L.L. undulatus "wavy, undulated," from undula "wavelet," diminutive of L. unda "wave."

Mowješ, verbal noun of mowjidan "to undulate," from mowj→ wave.

A prefix with the meaning of "one" occurring in loanwords from L., such as → uniform, → uniaxial, → universe, etc.

From uni- a combining form meaning "one," from L. uni-, from unus, → one;

Yek-, from yek, → one.

Crystal with double refraction possessing only one → optic axis.

→ uni-; axial adj. from → axis; → crystal.

The attribute of someone or something whose identity is not established. → unidentified flying object; → unidentified line.

→ un-; → identify.

Any flying object or phenomenon that cannot be identified by the observer.

→ unidentified; fly; M.E. flien; O.E. fleogan (cf. O.H.G. fliogan, O.N. flügja, M.Du. vlieghen, Ger. fliegen); → object.

A no longer in general use name for → Aromatic Infrared Band.

→ unidentified; → infrared; → band.

A spectral line whose origin is not clearly established. → line identification.

→ unidentified; → line.

1) The process of unifying or uniting; union.
2) The state or condition of being unified (Dictionary.com).

Verbal noun of → unify.

Without variations; identical, always the same in quality, degree, character, or manner.

→ uni- + → form.

Yekdis, from yek, → uni-, + dis, → form; yeknavâxt, literally "with one rhythm," from yek, → one, + navâxt "rhythm," from navâxtan, navâzidan "to play an instrument; to gratify," navâ "music, song, melody" (Mid.Pers. nw'c "to treat kindly, honour," niwag "music, melody;" Proto-Iranian *ni-uac-, from ni- "down; into," → ni- (PIE), + *uac- "to speak, treat kindly").

The motion of an object around a fixed point at a constant angular speed, and at constant radius.

→ uniform; → circular; → motion.

A field that at a given instant has the same value at all points within a specified region of interest.

→ uniform; field.

A → magnetic field whose direction does not change and whose strength is constant at every point.

→ uniform; → magnetic; → field.

Motion at a constant → velocity. The state of rest is a special case of uniform motion. → accelerated motion; → inertial motion.

→ uniform; motion.

1) Of, characterized by, or conforming to → uniformity.
2) Of or relating to → uniformitarianism.

→ uniformity + -arian.