Os

symbol

the chemical element osmium.

noun

a bone (used chiefly in Latin names of individual bones, e.g. os trapezium ).

Latin.

noun

an opening or entrance to a passage, especially one at either end of the cervix of the uterus.

mid 18th century: from Latin, ‘mouth’.

1. (in calculating dates) Old Style.
2. open-source.
3. operating system.
4. Ordinary Seaman.
5. (in the UK) Ordnance Survey.
6. (as a size of clothing) outsize.
7. out of stock.
8. overseas.

1. the fifteenth letter of the alphabet.
2. nought or zero (in a sequence of numerals, especially when spoken).

   two seven o seven point six

3. a shape like that of a capital O; a circle.

   he made an O with his mouth

noun

the method of calculating dates using the Julian calendar.

noun, symbol

the chemical element of atomic number 76, a hard, dense silvery-white metal of the transition series.

early 19th century: modern Latin, from Greek osmē ‘smell’ (from the pungent smell of its tetroxide).