Basil, Poor and Fair
If a coin is completely unidentifiable, it is in the basil state. Coins in the basil state are generally worth little more than the value of their metal content. An extremely well worn but identifiable coin with a readable date is in poor condition. Poor coins have little detail. Fair coins are like poor coins with slightly more detail. Fair coins can have holes in them or be bent.
Good
The good coin rating is broken into three different semi-ratings: about good, good and very good. About good coins have the rim worn away but are mostly readable. The rim is mostly intact on good coins, but the detail is still flat. Very good coins have a little more detail on the recessed points on the coin faces than about good or good coins.
Fine
Fine, like good, is broken down into three separate ratings: fine, very fine and extremely fine. A fine coin has sharp lettering and significant detail in the recessed areas of the coin faces. Very fine coins have a significant amount of detail still present on the faces of the coins. Some areas however are still noticeably worn. Extremely fine coins have light wear on the higher points of the coin.
About Uncirculated
About uncirculated coins are similar to extremely fine coins, except that they have even less wear. The coins have full details but have very slight wear on the highest points on the coin. These coins look in perfect condition to a novice, and they are often hard to distinguish from coins in mint state (also called uncirculated condition).
Mint and Proof
Mint state coins are in excellent condition. Virtually no wear is present, even on the absolute highest points of the coin. The best specimens of mint state coins will be absolutely perfect coins with a full strike (complete and outstanding details resulting from an exceptional minting) and no flaws. Proof coins are special coins made for collectors with reflective surfaces. They are not minted for circulation. Proof coins are graded in the same manner as mint state coins, but they tend to be worth more.