Chapter Equator to Equipotential of E by Webster's Dictionary (1913 Edition)

Equator to Equipotential

Equator
(E*qua"tor) n. [L. aequator one who equalizes: cf. F. équateur equator. See Equate.]

1. (Geog.) The imaginary great circle on the earth's surface, everywhere equally distant from the two poles, and dividing the earth's surface into two hemispheres.

2. (Astron.) The great circle of the celestial sphere, coincident with the plane of the earth's equator; - - so called because when the sun is in it, the days and nights are of equal length; hence called also the equinoctial, and on maps, globes, etc., the equinoctial line.

Equatorof the sun or of a planet (Astron.), the great circle whose plane passes through through the center of the body, and is perpendicular to its axis of revolution. — Magnetic equator. See Aclinic.

Equatorial
(E`qua*to"ri*al) a. [Cf. F. équatorial.] Of or pertaining to the equator; as, equatorial climates; also, pertaining to an equatorial instrument.

Equatorial
(E`qua*to"ri*al), n. (Astron.) An instrument consisting of a telescope so mounted as to have two axes of motion at right angles to each other, one of them parallel to the axis of the earth, and each carrying a graduated circle, the one for measuring declination, and the other right ascension, or the hour angle, so that the telescope may be directed, even in the daytime, to any star or other object whose right ascension and declination are known. The motion in right ascension is sometimes communicated by clockwork, so as to keep the object constantly in the field of the telescope. Called also an equatorial telescope.

The term equatorial, or equatorial instrument, is sometimes applied to any astronomical instrument which has its principal axis of rotation parallel to the axis of the earth.

Equatorially
(E`qua*to"ri*al*ly), adv. So as to have motion or direction parallel to the equator.

Equerry
(Eq"uer*ry) n.; pl. Equerries [F. écurie stable, for older escurie, escuirie (confused somewhat with F. écuyer, OF. escuyer, squire), LL. scuria, OHG. skiura, scra, barn, shed, G. scheuer, from a root meaning to cover, protect, and akin to L. scutum shield. See Esquire, and cf. Ecurie, Querry.]

1. A large stable or lodge for horses. Johnson.

2. An officer of princes or nobles, charged with the care of their horses.

In England equerries are officers of the royal household in the department of the Master of the Horse.

Equery
(Eq"ue*ry) n. Same as Equerry.

Equestrian
(E*ques"tri*an) a. [L. equester, from eques horseman, fr. equus horse: cf. F. équestre. See Equine.]

1. Of or pertaining to horses or horsemen, or to horsemanship; as, equestrian feats, or games.

2. Being or riding on horseback; mounted; as, an equestrian statue.

An equestrian lady appeared upon the plains.

Spectator.

3. Belonging to, or composed of, the ancient Roman equities or knights; as, the equestrian order. Burke.

Equestrian
(E*ques"tri*an), n. One who rides on horseback; a horseman; a rider.

Equestrianism
(E*ques"tri*an*ism) n. The art of riding on horseback; performance on horseback; horsemanship; as, feats equestrianism.