Some search engines may not specify the keyword used to reach your website (for example Google, DuckDuckGo, Firefox latest version now also removes keywords, etc.). Matomo (Piwik) will by default report the search keyword as “Keyword not defined”. It means that Matomo has detected that the visitor came from a search engine, but the keyword was not provided in the Referrer URL. But in 2017 we have developed a new solution which makes it possible to see all your keywords that users used to find you:
Learn more about how to import your Google, Bing and Yahoo Search keywords into your Matomo Analytics (formerly Piwik Analytics) reports in our Search Keywords Performance user guide.