The U.S. dollar uses the decimal system, consisting of 100 (equal) cents (symbol ¢). In another division, there are 1,000 mills or ten dimes to a dollar; additionally, the term eagle was used in the Coinage Act of 1792 for the denomination of ten dollars, and subsequently was used in naming gold coins.
In the second half of the 19th century there were occasional discussions of creating a $50 gold coin, which was referred to as a "Half Union," thus implying a denomination of 1 Union = $100. However, only cents are in everyday use as divisions of the dollar; "dime" is used solely as the name of the coin with the value of 10¢, while "eagle" and "mill" are largely unknown to the general public, though mills are sometimes used in matters of tax levies and gasoline prices.
When currently issued in circulating form, denominations equal to or less than a dollar are emitted as U.S. coins while denominations equal to or greater than a dollar are emitted as Federal Reserve notes (with the exception of gold, silver and platinum coins valued up to $100 as legal tender, but worth far more as bullion). (Both one-dollar coins and notes are produced today, although the note form is significantly more common.)
In the past, paper money was occasionally issued in denominations less than a dollar (fractional currency) and gold coins were issued for circulation up to the value of 20 dollars.
U.S. coins are produced by the United States Mint. U.S. dollar banknotes are printed by the Bureau of Engraving and Printing, and, since 1914, have been issued by the Federal Reserve. The "large-sized notes" issued before 1928 measured 7.42 inches by 3.125 inches; small-sized notes, introduced that year, measure 6.14 inches by 2.61 inches.
Notes above the $100 denomination ceased being printed in 1946 and were officially withdrawn from circulation in 1969. These notes were used primarily either in inter-bank transactions or by organized crime; it was the latter usage that prompted President Richard Nixon to issue an executive order in 1969 halting their use. With the advent of electronic banking, they became less necessary.
Notes in denominations of $500, $1,000, $5,000, $10,000, and $100,000 were all produced at one time; see large denomination bills in U.S. currency for details.
Nicknames
The colloquialism buck is often used to refer to dollars of various nations, including the U.S. dollar. This term, dating to the 18th century, may have originated with the colonial fur trade. Greenback is another nickname originally applied specifically to the 19th century Demand Note dollars created by Abraham Lincoln to finance the costs of the Civil War for the North. The original note was printed in black and green on the back side. It is still used to refer to the U.S. dollar (and not to the dollars of other countries).
Grand, sometimes shortened to simply G, is a common term for the amount of $1,000. The suffix K (from "kilo") is also commonly used to denote this amount (such as "$10K" being pronounced "Ten kay" to mean $10,000). Banknotes' nicknames are usually the same as their values (such as five, twenty, etc.)
The $5 bill has been referred to as a "fin" or a "fiver" or a "five-spot", and the $10 bill as a "sawbuck", a "ten-spot", or a "Hamilton", the $20 Bill as a "double sawbuck" or a "Jackson", the $1 bill is sometimes called a "single", the $2 bill a "deuce" or a "Tom" and the $100 bill is nicknamed a Benjamin, or "Benjie" (after Benjamin Franklin, who is honored on the note) or a C-note (C being the Roman numeral for 100) or a Century Note. Occasionally these will be referred to as "dead presidents", although neither Hamilton ($10) nor Franklin ($100) was President. $100 notes are occasionally referred to as 'large' in banking ("twenty large" being $2,000, etc.). The newer designs are sometimes referred to as "Bigface" bills.
In Panama, the translation of buck is palo (lit. stick); a nickname for the balboa (dollar). For example: Esto vale 20 palos ("This is worth 20 bucks").
Dollar sign
The symbol $, usually written before the numerical amount, is used for the U.S. dollar (as well as for many other currencies). An example would be "$45", which is read as "forty-five dollars".