os

name

1. (abbreviation, alt-of, initialism)Initialism of Owen Sound.
2. The Ordnance Survey, official mapping agency in Great Britain (see also the noun below).
3. (abbreviation, alt-of, initialism)Initialism of Old Saxon.

adj

1. (abbreviation, alt-of, initialism, not-comparable)Initialism of outsize, clothes for large people.
2. (abbreviation, alt-of, initialism, not-comparable)Initialism of oversize.
3. (abbreviation, alt-of, initialism, not-comparable)Initialism of Old Style, a term used in English language historical studies to indicate that a date conforms to the Julian calendar instead of the modern Gregorian calendar.
4. (abbreviation, alt-of, not-comparable)Abbreviation of offscreen, indicating a line of dialogue is spoken by someone not visible onscreen.
5. (abbreviation, alt-of, initialism, not-comparable)Initialism of over shoulder.

adv

1. (Australia, abbreviation, alt-of, informal, initialism, not-comparable)Initialism of overseas.

   “You did the overseas trip. You went OS.”

   “I kind of expanded my circle a bit more when I went OS [overseas].”

noun

1. (UK)An Ordnance Survey map.

   “We've got an OS of the Cuckmere area.”

   “Calton Hill in Edinburgh is located at OS grid ref NT262741.”

2. (abbreviation, alt-of, initialism)Initialism of operating system.

   “I've decided to install two different OSes on my new laptop.”

   “Some vendors do now have a variant of the per-unit royalty (usually termed a “shared risk,” or similar approach), but it is not strictly the same as for those proprietary embedded OSes mentioned before […]”

   “A policy-created scheduled task will be accepted by computers running client OSes as old as Windows 2000 […]”

   “In a dual-boot configuration, you install two OSs on the computer (Windows XP and Windows 2000, for example).”

3. (abbreviation, alt-of, initialism)Initialism of ordinary seaman.
4. (abbreviation, alt-of, initialism)Initialism of oppidan scholar.
5. Synonym of bone.

   “I was once, I remember, called to a Patient, who had received a violent Contuſion in his Tibia, by which the exterior Cutis was lacerated, ſo that there was a profuſe ſanguinary Diſcharge; and the interior Membranes were ſo divellicated, that the Os or Bone very plainly appeared through the Aperture of the Vulnus or Wound.”

6. (sometimes)An opening or entrance to a passage, particularly one at either end of the cervix, internal (to the uterus) or external (to the vagina).

   “The instrument closed, as seen in Fig. 1, is then passed along the finger to the os, in and through the cervix up to the fundus of the uterus, which may be determined both by the distance and the resistance to the broad rounded head of the Capiat.”

   “[…] monocolpate (“unisulcate”) pollen grains still have a continuous aperture membrane devoid of special openings (ora) in the exine for the emergence of the pollen tube.”

7. An osar or esker.
8. (alt-of, alternative, rare)Alternative form of o's.
9. (form-of, plural)plural of O