plural o's or os\
: the 15th letter of the English alphabet
: a graphic representation of this letter
: a speech counterpart of orthographic o
: a graphic device for reproducing the letter o
: one designated o especially as the 15th in order or class
: something shaped like the letter O
—used to express an emotion (such as surprise or desire) or in response to physical stimuli Oh, no! I forgot my key.Oh, don't stop!
—used in direct address oh, waiter! Will you come here, please?
—used to express acknowledgment or understanding of a statement Oh, yes. It's one of my favorite cities.
—used to introduce an example or approximation Their house is about, oh, I'd say four miles from here.
: the one of the four ABO blood groups characterized by the absence of antigens designated by the letters A and B and by the presence of antibodies against these antigens
[New Latin octarius]
—used as a connective vowel originally to join word elements of Greek origin and now also to join word elements of Latin or other origin speedometerelastomer
: one that is, has the qualities of, or is associated with
—in interjections formed from other parts of speech cheeriorighto