O

I

[[t]oʊ[/t]]

interj. n. pl. O's

1) (used before a name in direct address, esp. in solemn or poetic language, to lend earnestness to an appeal):

Hear, O Israel![/ex]

2) (used as an expression of surprise, pain, annoyance, longing, gladness, etc.)

3) the exclamation “O.”

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Etymology: 1125–75; ME < OF < L ō II

symb.

1) the 15th in order or in a series

2) the Arabic numeral; zero; cipher

3) phl a major blood group

Compare ABO system

4) chem. oxygen

III

1) Old

2) gram. Gram. object