Using words related to your keywords increases ownership of the subject.
We already know that keyword density plays a role in a page scoring high on keyword matching when people search the web for products or services like yours. But what about synonyms? Does Google know when you enter the word "chair", it should also look for "seat" or "bench"?
The answer is, Yes. Similar words play a significant role. They help a web page to be found by persons searching with related words and they reinforce a website's "ownership" of a topic.
Latent Semantic Content means words and terms commonly used when talking on the same subject, but which are not the exact keywords used on a web page.
For example, Dirty Dog Jeans' keywords might be "fashion handbag" and "designer handbag" and "designer jeans", but I do also want to use words and terms that are associated with my set of core keywords.
Similar words help a web page to be found by persons searching with related words and also, the reinforce a website's "ownership" of a topic.
Visit Google Sets, a little known function that provides a larger set of terms relating to a few you enter. Type the three keywords above, and you will get an interesting list of related terms:
designer handbag
fashion handbag
designer jeans
shoes store
wedding dress
designer clothes
designer purses
designer shoes
clothing store
designer wedding dresses
handbag designers
fashion accessory
As search engines pick up the use of these terms throughout the content on a website, in addition to core keywords, an "ownership" of the subject is perceived. This increases keyword matching score and makes it more likely the web page will appear higher up on search results.