A dyke (or dike) in geology is a type of later vertical rock between older layers of rock. Technically, it is any geologic body which cuts across:1  flat wall rock structures, such as bedding. dyke (or dike) in geology is a type of later vertical rock between older layers of rock. Technically, it is any geologic body which cuts across: 1  flat wall rock structures, such as bedding.
Another example would be the âdefault browserâ on your computer. Windows PCs come with Internet Explorer (the blue âEâ icon) as the default browser, just as Apple includes their own Safari browser as the default on their Mac computers.
To set Mozilla Firefox as your default Windows browser, take the following steps. 1  Open your Firefox browser. 2  Click on the Firefox menu button, represented by three horizontal lines and located in the upper right hand corner of the browser window. 3  When the pop-out menu appears, select Options.