It refers to an advertising product of search engine behemoth, Google.

Adwords has remained one of the major sources of revenue for Google for some years now. It offers site oriented advertising and pay per click based advertising like banner ads and text ads. Adwords are eligible to be shown on Google’s website. Advertisers also have an option showing their ad on Google’s other networks including their partners. Of lately, Adwords have been facing stiff competition from Microsoft adCenter and Yahoo! Search Marketing. The other co-product of Google is Adsense. This enables the website owners to make money from ads that get displayed on their sites. However, Google needs to be paid a commission if both Adsense and Adwords are to be used simultaneously to promote a website.