num. one, a —see Oon
adv. ever, aye, alwaysVariants: oo, a, aa, Comb.: a buten, ever without,; a bute, for ay and oo, for ever and everEtymology: Anglo-Saxon a (for áwa ); cp. Gothic aiw, ever. Cf. Ay
O is the Orange tree, that bloomed Beside his cabin door,When white men stole him from his home To see it never more.

O—the Ostrich

O'ER desert sands the Ostrich skims,
Beneath a burning sky;
Swift as the swiftest horse he runs,
But has no wings to fly.

O , Oh : Although often used indiscriminately it is generally conceded that “O” is used to express exclamation or direct address while “oh” is used to express the emotion of joy, pain, sorrow, or surprise. See the examples.

    “O Mary, go and call the cattle home.”     “O God, whose thunder shakes the skies.”

    “Oh! say, can you see by the dawn's early light”--     “Oh! why should the spirit of mortal be proud?”

O o.Obstinacy ,

The obstinacy of the pig

Is nature—as you see;

But boys and girls who have a mind

Should never stubborn be.