A collar for a dog or other animal that delivers electrical stimulation of varying intensity and duration to the neck via radio control.

(ergative) To (cause to) move in continuous contact with a surface. / (intransitive) To move on a low-friction surface. / (intransitive, baseball) To drop down and skid into a base.

plural of Spider sense (alternative form of Spidey-senses).

(mathematics) A cone of nullforms