os

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A mouth or an opening.
2. n. A bone.
3. n. See esker.

Century Dictionary and Cyclopedia

1. n. Bone; a bone.
2. n. A mouth; a passage or entrance into any place: an anatomical term; specifically, the mouth of the womb.
3. n. In geology, a Swedish term for certain elongated ridges of detrital material, generally considered to be of glacial origin, or in some not yet clearly explained way connected with the former presence of ice in the region where they occur. Some of these ridges in Sweden are over a hundred miles in length, and so regular in form that they are not infrequently used as roads. In Scotland they are called kames, in Ireland eskars. See eskar.
4. n. In chem., the symbol for osmium.
5. n. Same as os extrascapulare.
6. n. An abbreviation of the Latin Ordo Sancti Augustini, Order of St. Augustine.
7. n. An abbreviation of the Latin Ordo Sancti Benedicti, Order of St. Benedict.
8. An abbreviation of the Latin Ordo Sancti Francisci, Order of St. Francis.

Wiktionary

1. n. rare, medicine Bone.
2. n. rare A mouth; an opening.
3. n. In particular, either end of the cervix, internal (to the uterus) or external (to the vagina).
4. n. An osar or esker.

GNU Webster's 1913

1. n. A bone.
2. n. A mouth; an opening; an entrance.
3. n. (Geol.) One of the ridges of sand or gravel found in Sweden, etc., supposed by some to be of marine origin, but probably formed by subglacial waters. The osar are similar to the kames of Scotland and the eschars of Ireland. See eschar.
4. n. (Chem.) The chemical symbol for the element osmium.

WordNet 3.0

1. n. the left eye
2. n. a mouth or mouthlike opening
3. n. a hard brittle blue-grey or blue-black metallic element that is one of the platinum metals; the heaviest metal known
4. n. rigid connective tissue that makes up the skeleton of vertebrates
5. n. (computer science) software that controls the execution of computer programs and may provide various services