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A turning point; the principal or highest point; top; summit; crown; apex. Specifically: --(a) (Anat.)

The difference of direction of two lines. In the lines meet, the point of meeting is the vertex of the angle.

drawn to the body. -- Angular point, the point at which the sides of the angle meet; the vertex. -- Angular velocity, the ratio of anuglar motion to the time employed in describing.

the axis of a cylinder, i. e., the axis of a cone, that is, the straight line joining the vertex and the center of the base; the axis of a circle, any straight line passing through the center.

ough that vertical point; a solid having a circle for its base and tapering to a point or vertex.

The vertex or top of an arch; -- applied generally to about one third of the curve, but in a pointed arch to the apex only.

The forehead; the part of the cranium between the orbits and the vertex.

id body. Polyhedral angle, an angle bounded by three or more plane angles having a common vertex.

contained by a plane rectilineal figure as base and several triangles which have a common vertex and whose bases are sides of the base.

l conical refraction, in which the ray issues from the crystal in the form of a cone, the vertex of which is at the point of emergence; and internal conical refraction, in which the ray is changed into the form of a cone on entering the crystal, from which it issues in the form of a hollow cylinder. This singular pheno…

ii, or, more rarely, about any straight line drawn in the plane of the sector through its vertex.

One branch of a parabola, being terminated at the principal vertex of the curve.

The part of the head of a bird between the base of the bill and the vertex.

ion of the surface of an oblique cone with the surface of a sphere whose center is at the vertex of the cone.

le; applied also to two similar triangles when so placed as to have a common angle at the vertex, the opposite sides not being parallel. Brande & C.

of anything; the upper end, edge, or extremity; the upper side or surface; summit; apex; vertex; cover; lid; as, the top of a spire; the top of a house; the top of a mountain; the top of the ground. The star that bids the shepherd fold, Now the top of heaven doth hold. Milton.

the apex naturally drops off. Truncated cone or pyramid (Geom.), a cone or pyramid whose vertex is cut off by a plane, the plane being usually parallel to the base.

Of or pertaining to the vertex; situated at the vertex, or highest point; directly overhead, or in the zenith; perpendicularly above one. Charity . . . is the vertical top of all religion. Jer. Taylor.

isible. [R.] Visual angle. (Opt.) See under Angle. -- Visual cone (Persp.), a cone whose vertex is at the point of sight, or the eye. -- Visual plane, any plane passing through the point of sight. -- Visual point, the point at which the visual rays unite; the position of the eye. -- Visual purple (Physiol.), a phot…