A blood type that lacks A or B antigens and may only receive transfusions of similar type O blood, but may donate to all (neglecting Rh factor). Synonym: universal donor
Expression of earnestness or reverence, used before the name of a deity or revered person in impassioned speech
The English vocative particle (always in upper case), used for direct address in translations from languages which have the vocative case
O foolish Galatians, who hath bewitched you, that ye should not obey the truth, before whose eyes Jesus Christ hath been evidently set forth, crucified among you? -- Galatians 3:1.