Smallpox \Small"pox`\, n. [Small + pox, pocks.]

(Med.) A contagious, constitutional, febrile disease characterized by a peculiar eruption; variola. The cutaneous eruption is at first a collection of papules which become vesicles (first flat, subsequently umbilicated) and then pustules, and finally thick crusts which slough after a certain time, often leaving a pit, or scar.

Source: Webster's Revised Unabridged Dictionary (1913)