You can find most popular coin collecting phrases in this coin glossary.
nickel - nick name for the US five cent piece. Although only 25% of the five cent piece is made of the metal nickel it gives the appearance that it is solid nickel. The nick name "nickel" came about due to its appearance of being made of the metal nickel. It is actually made of a mixture of copper(75%) and nickel(25%).
novodel – a backdated coin struck from new dies.
numismatist - a coin collector. Often used to indicate someone who is a serious coin hobbiest or one who studies an area of coin collecting.
numismatics - hobby of coin collecting.