Google Adwords is the brand name for Google's popular pay per click advertising.
It is perceived as the best value Pay Per Click on the market, allowing low start up costs and many features to allow maximisation of budget spend.
Google AdSense is an ad-serving program operated by Google that provides relevant text, image, and video-based advertisements to enrolled site owners. Advertisers register via Google AdWords and pay for ads on a Pay-Per-Click, Cost-Per-Thousand or Cost-Per-Action basis.
from
google.com