| equator | 1. <geography> 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. <astronomy> 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. 3. <astronomy> Equator of the sun or of a planet, the great circle whose plane passes through through the center of the body, and is perpendicular to its axis of revolution. Origin: L. Aequator one who equalizes: cf. F. Equateur equator. See Equate. Source: Websters Dictionary (01 Mar 1998) |
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| equator bulbi oculi | An imaginary line encircling the globe of the eye equidistant from the anterior and posterior poles. Synonym: equator bulbi oculi. (05 Mar 2000) |
| equator lentis | The periphery of the lens lying between the two layers of the ciliary zonule. Synonym: equator lentis. (05 Mar 2000) |
| equator of eyeball | An imaginary line encircling the globe of the eye equidistant from the anterior and posterior poles. Synonym: equator bulbi oculi. (05 Mar 2000) |
| equator of lens | The periphery of the lens lying between the two layers of the ciliary zonule. Synonym: equator lentis. (05 Mar 2000) |
| equatorial | <astronomy> 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. Source: Websters Dictionary (01 Mar 1998) |
| equatorial cleavage | Cleavage in which the plane of cytoplasmic division is at right angles to the axis of the ovum. (05 Mar 2000) |
| equatorial division | Nuclear division in which each chromosome divides equally. (05 Mar 2000) |
| equatorial guinea | A republic in central africa, north of gabon and bounded on the west by the atlantic ocean. Its capital is malabo. Equatorial guinea was discovered by the portuguese in 1491 and ceded to spain in 1778. The country gained independence in 1968. Equatorial refers to its location near the equator in the broad region long known as guinea . (12 Dec 1998) |
| equatorial plane | In metaphase of mitosis, the plane that touches all of the centromeres and their spindle attachments. (05 Mar 2000) |
| equatorial plate | <cell biology> Region of the mitotic spindle where chromosomes are aligned at metaphase: as its name suggests, it lies midway between the poles of the spindle. (06 Mar 1998) |
| equatorial staphyloma | A staphyloma occurring in the area of exit of the vortex veins. Synonym: scleral staphyloma. (05 Mar 2000) |