Gecko is the name of the layout engine developed by the Mozilla Foundation. It was originally named NGLayout.
Gecko is used in many applications, including a few browsers, such as Firefox, Mozilla Suite, Camino, etc. (for a complete list, please refer to Wikipedia's article on Gecko.) Products using the same version of Gecko have identical support for standards.
Versions of Gecko
|Gecko version||Application based on it|
|Gecko 1.9 (under development)||Firefox 3|
|Gecko 1.8.1 (under development)||Firefox 2, SeaMonkey 1.1|
|Gecko 1.8||Firefox 1.5, Thunderbird 1.5, SeaMonkey 1.0|
|Gecko 1.7||Firefox 1.0, Thunderbird 1.0, Nvu 1.0, Mozilla Suite 1.7|
|older versions of Gecko match the Mozilla Suite versions|