Merriam-Webster Collegiate Dictionary - sty

 I. noun  (plural sties; also ~es)  Etymology: Middle English, from Old English stig pen; pigpen; akin to Old Norse svinsti pigpen  Date: before 12th century pigpen  II. verb  (stied or ~ed; ~ing)  Date: before 12th century  transitive verb to lodge or keep in a ~  intransitive verb to live in a ~  III. noun  or ~e  (plural sties or ~es)  Etymology: short for obsolete English ~an, from Middle English ~anye eye with a ~, from Old English stigend ~, from stigan to go up, rise — more at stair  Date: 1617 an inflamed swelling of a sebaceous gland at the margin of an eyelid