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traight line through the center of an object from side to side; width; thickness; as, the diameter of a tree or rock.

Half of a diameter; a right line, or the length of a right line, drawn from the center of a circle, a sphere, or other curved figure, to its circumference or periphery; a radius.

cream-of-tartar tree of Australia. Both have a trunk of moderate height, but of enormous diameter, and a wide-spreading head. The fruit is oblong, and filled with pleasantly acid pulp. The wood is very soft, and the bark is used by the natives for making ropes and cloth. D. C. Eaton.

the length of the neck of a retort, or to unite two vessels whose openings have different diameters. [Written also adapter.]

The diameter of the exposed part of the object glass of a telescope or other optical instrument; as, a telescope of four-inch aperture.

d from, but not necessarily opposed to, true or real); seeming; as the apparent motion or diameter of the sun. To live on terms of civility, and even of apparent friendship. Macaulay. What Berkeley calls visible magnitude was by astronomers called apparent magnitude. Reid. Apparent horizon, the circle which in a level…

h, from internal pressure, flows spontaneously like a fountain. They are usually of small diameter and often of great depth.

, horizon (or other circle considered with reference to the sphere on which it lies), the diameter of the sphere which is perpendicular to the plane of the circle. Hutton. -- Axis of the Ionic capital (Arch.), a line passing perpendicularly through the middle of the eye of the volute. -- Neutral axis (Mech.), the lin…

n the hearth. [U.S.] There was first a backlog, from fifteen to four and twenty inches in diameter and five feet long, imbedded in the ashes. S. G. Goodrich.

ock of some tough stone, esp. granite, used as a material for street pavements. Its usual diameter is 5 to 7 inches.

Of or pertaining to the diameter of the cranium, from one parietal fossa to the other.

The size of a hole; the interior diameter of a tube or gun barrel; the caliber.

esp. the South Sea islands. It is of a roundish form, from four to six or seven inches in diameter, and, when baked, somewhat resembles bread, and is eaten as food, whence the name.

ous small green heads, or "sprouts," each a cabbage in miniature, of one or two inches in diameter; the thousand-headed cabbage. -- Brussels wire ground, a ground for lace, made of silk, with meshes partly straight and partly arched.

The diameter of the bore, as a cannon or other firearm, or of any tube; or the weight or size of the projectile which a firearm will carry; as, an 8 inch gun, a 12-pounder, a 44 caliber. The caliber of empty tubes. Reid. A battery composed of three guns of small caliber. Prescott.

t, usually resembling a pair of dividers or compasses with curved legs, for measuring the diameter or thickness of bodies, as of work shaped in a lathe or planer, timber, masts, shot, etc.; or the bore of firearms, tubes, etc.; -- called also caliper compasses, or caliber compasses. Caliper square, a draughtsman's or m…

at part of the bore of a piece of ordnance which holds the charge, esp. when of different diameter from the rest of the bore; -- formerly, in guns, made smaller than the bore, but now larger, esp. in breech-loading guns.

In a shotgun, a bore which is tapered to a slightly smaller diameter at a short distance (usually 2½ to 3 inches) to the rear of the muzzle, in order to prevent the rapid dispersion of the shot.

ty of bacteria, a vegetable organism, generally less than a thousandth of a millimeter in diameter.

A pulley for driving machines, etc., having two or more parts or steps of different diameters; a pulley having a conical shape.