Search the Dictionary

A measure of surface in the metric system containing ten thousand ares, or one million square meters. It is equal to about 247.1 acres.

naked masses of protoplasm, often of considerable size, which creep very slowly over the surface and ingest solid food. -- Myx`o*my*ce"tous (#), a.

Woolly or villous surface of felt, cloth, plants, etc.; an external covering of down, of short fine hairs or fibers forming part of the substance of anything, and lying smoothly in one direction; the pile; -- as, the nap of cotton flannel or of broadcloth.

Sheet; surface; all that portion of a surface that is continuous in such a way that it is possible to pass from any one point of the portion to any other point of the portion without leaving the surface. Thus, some hyperboloids have one nappe, and some have two.

, the method of determining a ship's position, course, distance passed over, etc., on the surface of the globe, by the principles of geometry and astronomy.

Of or pertaining to a region of the earth's surface including all of temperate and arctic North America and Greenland. In the geographical distribution of animals, this region is marked off as the habitat certain species.

Belonging to, or designating, a region of the earth's surface which comprises most of South America, the Antilles, and tropical North America.

s or other compounds. Contrasted with Ant: acid, and Ant: alkaline. Neutral axis, Neutral surface (Mech.), that line or plane, in a beam under transverse pressure, at which the fibers are neither stretched nor compressed, or where the longitudinal stress is zero. See Axis. -- Neutral equilibrium (Mech.), the kind of e…

A broken or indented place in any edge or surface; nicks in china.

To catch and inclose or compress tightly between two surfaces, or points which are brought together or closed; to pinch; to close in upon. May this hard earth cleave to the Nadir hell, Down, down, and close again, and nip me flat, If I be such a traitress. Tennyson.

A straight line or plane drawn from any point of a curve or surface so as to be perpendicular to the curve or surface at that point.

The back or upper surface, as of a bird.

A name for certain crustaceous marine algæ which secrete carbonate of lime on their surface, and were formerly thought to be of animal nature. They are now considered corallines of the genera Melobesia and Lithothamnion.

The whole body of salt water which covers more than three fifths of the surface of the globe; -- called also the sea, or great sea. Like the odor of brine from the ocean Comes the thought of other years. Longfellow.

One of the more or less columnar cells on the outer surface of the pulp of a tooth; an odontoplast. They are supposed to be connected with the formation of dentine.

he face of a wall, formed by a diminution of its thickness, or by the weathering or upper surface of a part built out from it; -- called also set-off.

At, or in contact with, the surface or upper part of a thing, and supported by it; placed or lying in contact with the surface; as, the book lies on the table, which stands on the floor of a house on an island. I stood on the bridge at midnight. Longfellow.

Wavy; having the surface marked by waves or slightly depressed furrows; as, ondoyant glass.

instrument devised by Helmholtz for measuring the size of a reflected image on the convex surface of the cornea and lens of the eye, by which their curvature can be ascertained.

a) A line drawn through the center of the eye perpendicular to its anterior and posterior surfaces. In a normal eye it is in the direction of the optic axis that objects are most distinctly seen. (b) The line in a doubly refracting crystal, in the direction of which no double refraction occurs. A uniaxial crystal has o…