browser.urlbar.matchOnlyTyped

[for Firefox users]
When you type a web address in the location bar of Mozilla Firefox, a drop-down list will appear, showing entries in your browser history that match what you have typed so far. Sometimes people only want entries that have been previously typed. Well, there’s a preference setting for that.

Enter about:config in the location bar.
Search for the preference browser.urlbar.matchOnlyTyped.
Modify the value to true.