ace

Numismatic nickname for a $1 bill, particularly a $1 National Bank Note of the Original Series or the Series of 1875.

alloy

A combination of two or more metals.

altered

A coin that has been intentionally changed to make it appear to be a rarer or more valuable issue, or in a better state of preservation.

altered date

A false date on a coin; a date altered after the coin was made to make it appear to be one of a rarer or more valuable issue.

American Bank Note Company

Firm founded in 1858 in New York City. Provider by contract of certain federal currency and Fractional Currency notes in the 1860s through the mid-1870s. Sometimes one private firm would print the face of a note and another would print the back. In all instances, the Treasury seals were separately imprinted by the Treasury Department in Washington, D.C. The ABNCo monogram appears on certain Fractional Currency and early federal notes of the 1860s.

assay

A test to determine the fineness (weight and purity) of a metal.

Aureate

Golden in color.

authentication

The process of determining the genuineness of a coin or bank note.