potassium iodide

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A white crystalline compound, KI, used in photography and medicine, as an analytical reagent, and in table salt as a source of dietary iodine.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun chemistry a salt, KI, formally derived from potassium hydroxide and hydriodic acid, used as an analytical reagent, in organic synthesis, and in the preparation of photosensitive emulsions and as a radioprotector to protect the thyroid.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a crystalline salt in organic synthesis and in making photographic emulsions and in iodized table salt