Adwords is Google's advertising network.

Google Adwords is an advertising network that is ran by Google. Companies will often bid on adverts that will appear in certain SERPs. Adwords gives their users a lot of information, so they can decide which phrase is better to bid on. So for instance, if a footwear company wants to sell more flip flops then it may want to advertise on Google, but many companies will probably want to be advertised on the “flip flop” SERP, so it would be wiser to bid on a keyword phrase that is more niche such as “cheap flip flops for holiday”. An Adwords account will show users the most popular search terms, how often it is searched and the average CPC.