CPC stands for Cost Per Click.
It is also known as PPC or Pay Per Click bidding.
Your CPC is the cost of a click your on your ad – what you as the advertiser will pay for that click.
Different factors affect your CPC, including how competitive that keyword is, your own maximum bids, bid adjustments, certain bid strategies (such as ECPC) and your Quality Score.
Keyword competitiveness determines whether the keyword has a high cost or not – some industries, such as the insurance and law industries, are known to have a higher cost at the keyword level because the keywords they use are very competitive.
You will need to set a Max. Bid – this is the maximum you are willing to pay for a click and the typical price that you will be charged for each click.
Your Max. Bid enters into the ad auction and depending on other factors mentioned above, you can either pay up to your Max. Bid or, in some cases less.
Because your Max. CPC is not necessarily what you will pay for a click (it could be less), the final amount is called Actual CPC.