Borrowed from Latin os.

• (RP) IPA: /ɒs/
• (America) IPA: /ɑs/

os (plural ossa)

1. (anatomy) Synonym of bone.
   • 1749, Henry Fielding, “Containing the great Address of the Landlady; the great Learning of a Surgeon, and the solid Skill in Casuistry of the worthy Lieutenant”, in The History of Tom Jones, a Foundling, volume III, London: A[ndrew] Millar, […], →OCLC ↗, book VII, page 109 ↗:

     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.

• French: os
• German: Os
• Italian: osso
• Spanish: hueso

• (RP) IPA: /ɒs/
• (America) IPA: /ɑs/

os (plural ora)

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

   Synonyms: orifice

Borrowed from Swedish ås.

• (RP) IPA: /ɒs/
• (America) IPA: /ɑs/

os (plural osar)

1. An osar or esker.

From o + -s.

• (RP) IPA: /əʊz/
• (America) IPA: /oʊz/

1. (rare) Alternative form of o's.

Abbreviation of Latin oculus sinister.

• IPA: /ˌoʊ ˈɛs/

1. (sports) Abbreviation of Owen Sound
2. The Ordnance Survey, official mapping agency in Great Britain (see also the noun below).

   Related terms: OSNI

os (not comparable)

1. Abbr of outsize (clothes for large people)
2. Abbr of oversize
3. Abbr 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. (screenwriting) Abbr of offscreen indicates a line of dialogue is spoken by someone not visible onscreen

os (not comparable)

1. (AU, informal) Abbr of overseas
   • 2015, Mick Houghton, I've Always Kept a Unicorn: The Biography of Sandy Denny:

     You did the overseas trip. You went OS.

   • 2022, The Betoota Advocate, The Australian Dream: Sell everything and move to Betoota, page 33:

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

os (plural oss or es)

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. (software) Initialism of operating system

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

3. Abbreviation of ordinary seaman

• Portuguese: SO

1. plural form of O