Definition: Firefox

A once-popular open source Web browser for Windows, Mac and Linux from the Mozilla project. Including a search box for Google and other major sites, Firefox is customizable by adding "extensions," such as a stock tracker, autofill and hundreds of others.

Quite an Impact in the 2000s
Introduced in 2004, Firefox achieved a lot of notoriety, and by mid-2005 captured more than 10% of the browser market. Reaching approximately 30% by 2010, usage declined to less than 5% by 2024 due to the popularity of the Chrome browser.

Many viewed Firefox as a more secure alternative to Internet Explorer (IE), which was always under attack. Pundits argue whether Firefox is safer because of better design or simply that hackers have no quarrel with open source software.

A Ghost from the Past
Firefox stemmed from the Netscape browser, which was a casualty of the browser wars in the late 1990s. After Netscape evolved into a very large and somewhat bloated application, it was turned into the open source Mozilla project. See Internet Explorer and Netscape.

In the early 2000s, the Gecko rendering engine was excised out of Mozilla and combined with the XUL user interface language to create a leaner, faster Mozilla browser. Renamed Phoenix, then Firebird, it finally gave birth as Firefox. See Firefox OS, Netscape, Mozilla, XUL and Greasemonkey.

Firefox on the Mac

An innovative browser, Firefox was one of the first to organize viewing history and provide tabs.