Use synonyms for your keywords

Synonyms, like keyword stemming is another way to mix up your text for your readers while still optimizing for search. Most modern search engines have a powerful synonym library and so recognize that words like "dog" and "canine" mean the same thing. Be careful using this technique on non-English pages, however. Most search engines were developed in English-speaking countries, and have more extensive English vocabularies than other languages. Also, you should remember that tools like keyword density readers often don't recognize synonyms, so your page may be denser in keywords than they report if you use a lot of synonyms.