Jigger \Jig"ger\ (j[i^]g"g[~e]r), n. (Zo["o]l.) Any one of several species of small red mites (esp. {Tetranychus irritans} and {T. Americanus}) which, in the larval or leptus stage, burrow beneath the skin of man and various animals, causing great annoyance. [Southern U. S.]