Keywords 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.

Basically There are 3 Types of Keywords:-

1. Keyword of Single word:- 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.
2. Keyword of Multiple words:- Keyword of Multiple words is used to target a specific traffic, which leads to high sale, top position in search result listing as well as improves page rank competition. Keyword of Multiple words are known as Specific Keyword where we target a specific audience & not general searcher. Keyword of Multiple words helps to target a specific page for a specific audience.
3. Keywords based on Theme:- Keywords based on Theme are used in each page of web site to focus on a specific topic correlated to a targeted topic or idea . Keywords based on Theme effectively contribute in growth of informative pages for its site focusing on different related topics.