Coin dealers/collectors use a jargon peculiar to this industry.  Here are several of the common terms:

Mint Mark - Alphabetic character indicating where the coin was produced.  These may be either on the front or the back.

Obverse - indicates the front of the coin

Reverse - indicates the back of the coin

Reeded edge - the notches around the rim of the coin.  Used to show signs of "clipping".

Clipping - done more in old times.  Merchants would shave/clip the edges of coin, reducing the weight.  They would save these clippings and melt them down.

Wear - as coins are circulated throughout the nation, they "wear".  Each coin has its own particular "wear" points that are critical to examine when grading coins.  It can take a very well trained eye to decipher some of the finer points in grading.

"Slabbed" coins - This term is used on coins that have been sent into a specialized third party grading service.  These services are NGC (Numismatic Guaranty Corporation), PCGS (Professional Coin Grading Service) and ANACS (American Numismatic Association Coin Services).

These are independent grading services whose grading systems are trusted world wide.

The coins are graded for a fee and are returned to the owner, graded, and placed in a hermetically sealed plastic holder (slab).  The coin and grade details are also placed within this holder.