Keyword can be classified into three categories :
Keyword(s) are basic raw material used in Search Engine Optimization (SEO). Keyword selection must be done using Keyword Research where we use special tools to find out a list of Keywords (search terms) searched by targeted audience, recently. Keyword can be single word, two or three words, multiple words and theme based.
Lets detail each of these one by one . Understanding these categories of keywords would also help one to decide as to their targeting on specific pages.
Keyword of Single word
Keyword of Single word is used to target a large traffic but leads to highly competition category of sites. Keyword of Single word are known as generic Keyword(s) where we target general audience. Keyword of Single word does not help to target a specific page for a specific audience.
Although, Keyword of Single word helps in bringing huge traffic but these terms are mostly not relevant these days, as, searchers mostly use two or three keyword to find out their required information.
Instead single word keywords are good theme keywords.
We can use these primary keyword 5 to 7 times in a web page for good theming according of a site. The inside pages of the site can qualify these themes into product or service categories by adding qualifiers to these theming keywords.
Example:
Keyword