The United States twenty-dollar bill ($20) is a denomination

Denomination (currency)

Denomination is a proper description of a currency amount, usually for coins or banknotes. Denominations may also be used with other means of payment like gift cards. See also Redenomination.-Subunit and super unit:...

 of United States currency

United States dollar

The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....

. U.S. President

President of the United States

The President of the United States of America is the head of state and head of government of the United States. The president leads the executive branch of the federal government and is the commander-in-chief of the United States Armed Forces....

 Andrew Jackson

Andrew Jackson

Andrew Jackson was the seventh President of the United States . Based in frontier Tennessee, Jackson was a politician and army general who defeated the Creek Indians at the Battle of Horseshoe Bend , and the British at the Battle of New Orleans...

 is currently featured on the front side of the bill, which is why the twenty-dollar bill is often called a "Jackson," while the White House

White House

The White House is the official residence and principal workplace of the president of the United States. Located at 1600 Pennsylvania Avenue NW in Washington, D.C., the house was designed by Irish-born James Hoban, and built between 1792 and 1800 of white-painted Aquia sandstone in the Neoclassical...

 is featured on the reverse side.

The twenty-dollar bill in the past was referred to as a "double-sawbuck" because it is twice the value of a ten-dollar bill

United States ten-dollar bill

The United States ten-dollar bill is a denomination of United States currency. The first U.S. Secretary of the Treasury, Alexander Hamilton, is currently featured on the obverse of the bill, while the U.S. Treasury is featured on the reverse. The United States ten-dollar bill ($10) is a...

, which was nicknamed a "sawbuck" due to the resemblance the Roman numeral for ten (X) bears to the legs of a sawbuck

Sawbuck

A sawbuck is a device for holding rough wood so that it may be sawn into pieces of length usable in a stove or fireplace. Easily made in the field from rough material, it consists of two "X" forms, one at each end, which are stabilized by a central piece...

, although this usage had largely fallen out of favor by the 1980s.