1867 P. G. Tait tr. Helmholtz in 4th Ser. 33 486 By vortex-filaments..I denote portions of the fluid bounded by vortex-lines drawn through every point of the boundary of an infinitely small closed curve.
1878 W. K. Clifford iii. 203 The part of the body inside the tube is called a vortex-filament.