A glass of liquor. Obsolete in England, though Douglas Jerrold (1851) has a “horn of ale.” (N.E.D.)

1

1682.  He went to Queen’s College,… and had a horne of beere.—Wood, ‘Life,’ May 31. (N.E.D.)

2

1824.  I went to bed after taking but one horn.—The Microscope, Albany, April 3.

3

1824.  See WORK LIKE A BEAVER.

4

1837.  One day he was leaning against a post, reflecting upon the expedient he should next devise to obtain a ‘horn,’ when his forlorn appearance attracted the attention of a gentleman, who stopped a moment to observe more completely his wretchedness.—Knick. Mag., x. 255 (Sept.).

5

1840.  I ’ll bet you a horn of Monongahela whiskey, old fellow, that you have had your supper.—Id., xvi. 236 (Sept.).

6

1840.  He called lustily for a horn of baldface and molasses.—Daily Pennant, St. Louis, April 28.

7

1845.  There was a suspension of hostilities, in order that the belligerents might take a horn and warm their fingers.—Bangor Mercury, n.d.

8

1848.  Here’s jest a leetle horn a piece in the bottle—let’s licker once more round, and then absquattle.—W. E. Burton, ‘Waggeries,’ p. 17 (Phila.).

9

1848.  

        I wears no crape upon my hat,
  ’Cause I’m a packin’ sent—
I only takes a extra horn,
  Observing, “LET HER WENT!”
Durivage and Burnham, ‘Stray Subjects,’ p. 109.    

10

1853.  I would rather not take a horn now, said the loafer to a mad bull; but the bull insisted on treating, and the loafer got quite high.—Daily Morning Herald, St. Louis, May 5.

11

1857.  My opinion is that Mark was invited to take a horn, in which case, I’m bold to say, the horn was taken.—S. H. Hammond, ‘Wild Northern Scenes,’ p. 198.

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