Keywords and Key Terms
Key terms or keywords (often more than one word) are queries by search engine users to find the information that they are looking for. Research should be conducted to identify the most and least used search terms or keywords relevant to your web page.
Once the key terms or keywords are identified, they should be incorporated into the web page in a manner which would not constitute abusing the search engine.
Search engines are misled by artificially inflating the density of key term although a higher density of key terms in a web page may lead to higher search engine rankings. As a rule of thumb, if the web page is not unbearable to read it is usually acceptable.
It is also advisable to ensure your domain name includes a key term or keywords relevant to your website.
The domain name of a website is a primary factor used by search engines to rank a website according to relevancy algorithms.
One recommended resource to help identify key terms is Wordtracker. This tool gives suggestions based on over 300 million key terms used by users from Metacrawler.com and Dogpile.com with the actual frequency of key term and the predicted frequency. This offers a free trial but does require a license for extended use.