n.; pl. E. Vortexes L. Vortices [ L. vortex, vertex, -icis, fr. vortere, vertere, to turn. See Vertex. ] [ 1913 Webster ]

1. A mass of fluid, especially of a liquid, having a whirling or circular motion tending to form a cavity or vacuum in the center of the circle, and to draw in towards the center bodies subject to its action; the form assumed by a fluid in such motion; a whirlpool; an eddy. [ 1913 Webster ]

2. (Cartesian System) A supposed collection of particles of very subtile matter, endowed with a rapid rotary motion around an axis which was also the axis of a sun or a planet. Descartes attempted to account for the formation of the universe, and the movements of the bodies composing it, by a theory of vortices. [ 1913 Webster ]

3. (Zool.) Any one of numerous species of small Turbellaria belonging to Vortex and allied genera. See Illustration in Appendix. [ 1913 Webster ]

Vortex atom (Chem.), a hypothetical ring-shaped mass of elementary matter in continuous vortical motion. It was conveniently regarded in certain early mathematical models as the typical form and structure of the chemical atom, but is no longer considered a useful model, having been superseded by quantum mechanics. --
Vortex wheel, a kind of turbine. [ 1913 Webster +PJC ]

. A vortex tube of infinitesimal cross section. [ Webster 1913 Suppl. ]

. The region immediately surrounding a disk moving flatwise through air; -- so called because the air has a cyclic motion as in vortex ring. [ Webster 1913 Suppl. ]

. A line, within a rotating fluid, whose tangent at every point is the instantaneous axis of rotation as that point of the fluid. [ Webster 1913 Suppl. ]

. (Physics) A ring-shaped mass of moving fluid which, by virtue of its motion of rotation around an axis disposed in circular form, attains a more or less distinct separation from the surrounding medium and has many of the properties of a solid. [ Webster 1913 Suppl. ]

. (Chem. & Physics) The theory, advanced by Thomson (Lord Kelvin) on the basis of investigation by Helmholtz, that the atoms are vortically moving ring-shaped masses (or masses of other forms having a similar internal motion) of a homogeneous, incompressible, frictionless fluid. Various properties of such atoms (
vortex atoms) can be mathematically deduced. This theory is now (1998) obsolete, and has been superseded by quantum mechanics, which provides more accurate and detailed explanations of atomic behavior. [ Webster 1913 Suppl. +PJC ]

. (Physics) An imaginary tube within a rotating fluid, formed by drawing the vortex lines through all points of a closed curve. [ Webster 1913 Suppl. ]