Motto of the United States of America, indicating that a single nation was made by uniting many states or a reference to the many states in the United States as being one nation. It may have been adapted from a line in Virgil's poem, "Moretum" which deals with the making of a salad and reads color est e pluribus unus, probably the first use of the phrase in any form. There was also an essay by Richard Steele in The Spectator, August 20, 1722, which opens with the Latin phrase Exempta juvat spiris e pluribus unus: "Better one thorn plucked than all remain."
The Continental Congress ordered the President of Congress to construct a seal in 1776 and E Pluribus Unum appeared on the first seal, as well as on many early coins. Congress adopted the motto in 1781 and it still appears on U.S. coins as well as on the Great Seal of the United States.
"Just a month after the completion of the Declaration of Independence, at a time when the delegates might have been expected to occupy themselves with more pressing concerns—like how they were going to win the war and escape hanging—Congress quite extraordinarily found time to debate the business of a motto for the new nation. (Their choice, E Pluribus Unum, ‘One from Many,' was taken from, of all places, a recipe for salad in an early poem by Virgil.)"
The translated poem, "Moretum", attributed to Virgil, lines 101-106
Then grinds everything equally in a juicy mixture.
The hand goes in circles: gradually the separate essences
Lose distinction, the color is out of many one [e pluribus unus],
Neither all green, since milky-white bits resist it,
Nor shining milky white, since the herbs are so various.
Virgil used unus because "color" is masculine in Latin; we use the neuter form unum because the United States is considered neuter (neither masculine nor feminine).
Thomas Jefferson is given credit for having suggested E pluribus unum, which was at that time integrated into the first version of the Great Seal in 1776 and has remained there ever since.