You can find most popular coin collecting phrases in this coin glossary.
keel boat - United States five cent nickel issued in 2004. Features a picture of the keel boat that Lewis and Clark used on their expedition. Captains Lewis and Clark can be seen in full uniform in the bow of the keelboat.
key date - a scarce date that is often hard to find to complete a collection. Usually more difficult to find, of lower mintage, or more expensive.
kilogram - one thousand grams. Equals about 32.15 troy ounces. Also see "gram" .