BUT.
331. (1) Coördinate conjunction: (a) Adversative.
His very attack was never the inspiration of courage, but the result of calculation.—Emerson.
(b) Copulative, after not only.
Then arose not only tears, but piercing cries, on all sides. —Carlyle.
(2) Subordinate conjunction: (a) Result, equivalent to that ... not.
Nor is Nature so hard but she gives me this joy several times.—Emerson.
(b) Substantive, meaning otherwise ... than.
Who knows but, like the dog, it will at length be no longer traceable to its wild original—Thoreau.
(3) Preposition, meaning except.
Now there was nothing to be seen but fires in every direction.—Lamb.
(4) Relative pronoun, after a negative, stands for that ... not, or who ... not.
There is not a man in them but is impelled withal, at all moments, towards order.—Carlyle.
(5) Adverb, meaning only.
The whole twenty years had been to him but as one night.—Irving.
To lead but one measure.—Scott.