The cant or vulgar name of the United States Government; sometimes called Brother Jonathan. It is used as John Bull is in England. Mr. Frost, in his Naval History of the United States, gives the following account of the origin of the name
"Immediately after the last declaration of war with England, Elbert Anderson of New York, then a contractor, visited Troy, on the Hudson; where was concentrated, and where he purchased, a large quantity of provisions, beef, pork, &c. The inspectors of these articles at that place were Messrs. Ebenezer and Samuel Wilson. The latter gentleman (invariably known as 'Uncle Sam') generally superintended in person a large number of workmen, who, on this occasion, were employed in overhauling the provisions purchased by the contractor for the army. The casks were marked 'E. A.--U. S.' This work fell to the lot of a facetious fellow in the employ of the Messrs. Wilson, who, on being asked by some of his fellow-workmen the meaning of the mark (for the letters U. S. for United States, were then almost entirely new to them), said, 'he did not know, unless it meant Elbert Anderson and Uncle Sam'--alluding exclusively, then, to the said 'Uncle Sam' Wilson. The joke took among the workmen, and passed currently; and 'Uncle Sam' himself being present, was occasionally rallied by them on the increasing extent of his possessions." P. 297.
"Many of these workmen, being of a character denominated 'food for powder,' were found, shortly after, following the recruiting drum, and pushing toward the frontier lines, for the double purpose of meeting the enemy, and of eating the provisions they had lately labored to put in good order. Their old jokes accompanied them, and before the first campaign ended, this identical one first appeared in print; it gained favor rapidly, till it penetrated and was recognised in every part of the country, and will, no doubt, continue so while the United States remain a nation." Ibid.