aplanatic
(adjective) free from or corrected for spherical aberration; “an aplanatic mirror”
Source: WordNet® 3.1
aplanatic (comparative more aplanatic, superlative most aplanatic)
(optics, of an optical system) Free from, or corrected for, spherical aberration and chromatic aberration
• antapical
Source: Wiktionary
Ap`la*nat"ic, a. Etym: [Gr. (Opt.)
Definition: Having two or more parts of different curvatures, so combined as to remove spherical aberration; -- said of a lens. Aplanatic focus of a lens (Opt.), the point or focus from which rays diverging pass the lens without spherical aberration. In certain forms of lenses there are two such foci; and it is by taking advantage of this fact that the best aplanatic object glasses of microscopes are constructed.
Source: Webster’s Unabridged Dictionary 1913 Edition
17 March 2025
(noun) magnet made of a substance whose magnetization is proportional to the strength of the magnetic field applied to it
The first coffee-house in Mecca dates back to the 1510s. The beverage was in Turkey by the 1530s. It appeared in Europe circa 1515-1519 and was introduced to England by 1650. By 1675 the country had more than 3,000 coffee houses, and coffee had replaced beer as a breakfast drink.
