The dime, in United States usage, is a ten-cent coin (10¢), one tenth of a United States dollar, labelled formally as "one dime". After the half dime became five cents in 1873, the dime is now the only United States coin in general circulation that is not denominated in terms of dollars or cents.
The denomination exists since the introduction of US currency. It was initially a larger silver coin featuring the draped bust of Liberty (1796 - 1807), then a smaller capped bust of Liberty (1809 - 1837), then with a Seated Liberty obverse (1837 - 1891) which was in turn replaced by the Barber Dime (1892 - 1916).
The so-called Mercury Dime was introduced in 1916. Designed by Adolph Weinman and also referred to as the Winged Liberty Head Dime, it gained its common name because the obverse depiction of a young Liberty, identifiable by her winged Phrygian cap, was confused with the Roman god Mercury. The coin's reverse depicts a fasces - a Roman simbol of authority, unity and strength, and an olive branch signifying peace. Its composition, like that of earlier dimes, is 90% silver and 10% copper.
The coin continued to be minted until 1945, when the Treasury ordered that a new design, featuring recently deceased president Franklin Roosevelt, take its place. In later years, the composition of the dime was debased to copper-nickel, and silver coinage disappeared from circulation. However, these coins have never been demonetised and are still legal tender. This, of course, is of academic interest only, as their numismatic and bullion value is much higher than their face value.
Within a plain rim, the obverse of the coin shows a portrait of Miss Liberty facing left, the tight curls of her hair caught in a Phrygian cap (pileus) which is winged. The coin is known as the Mercury Dime because of the resemblance of this portrait with depictions of Mercury, the Roman god of commerce and communications.
Around above in large letters, the word LIBERTY is partly obscured by the top of the cap.
On two lines below left, the national motto IN · GOD WE · TRUST.
The designer's monogram WA (W over A), for Adolph Weinman, is in the field below right, between the Y of LIBERTY and last digit of the date.
Below right, under the neck truncation of the portrait, the date: [year].
Within a plain rim, the reverse of the coin depicts at its centre a bundle of "fasces" (sticks) wrapped around an axe and bound both horizontally and diagonally by a leather strap, with the loose ends at the bottom. This object was carried by the lictors (assistants) who accompanied a Roman magistrate and was a symbol of his powers - sticks for his authority to inflict corporal punishment, and the axe for his authority to issue a death sentence. Incidentally, the word "fasces" is the root of the word "fascism" - an ideology which took it as a symbol of the State's power to establish law and order.
On this coin, the symbol represents war and justice. It is contrasted with a large olive branch as a symbol of peace.
The lettering is in Roman style; around above, UNITED · STATES · OF · AMERICA; separated from this by two five-pointed stars, and divided by the bottom part of the fasces, the value and denomination ONE DIME. In the right field, on two lines the motto E · PLURIBUS UNUM ("Out of many, one" - signifying unity in diversity).
Coins struck by the Philadelphia Mint have no mint mark. Coins struck by other mints have a mint mark in the form of a small letter below the base of the olive branch, after the letter E of ONE.