Component/features that is provided with the product as you bring the server up and are ready to be used as is are termed as OOTB component.
Offcourse these feature can be extended further and can be combined with each other to achieve complex scenarios.
For example, if you create an adaptive form you get text field component, date picker, drop-down component and so on; these can be used as is. You can also create your own component by extending OOTB component.