In terms of computing (such as PCI and PCIe cards), they are used to quite literally 'extend' the capabilities of a computer.
For example, you could add a graphics card for gaming/video editing or a maths coprocessor if you have a need for it.
Other example include NICs that allow you connect to the internet (most computers have one built into the motherboard nowadays) and audio cards.
Hope this helps!
PCI cards
Extension cards. (What else did you think of, decoration?)
The versatile extension clamp is used to set up lab equipment including distillation. Extension clamps are used where an extension is needed and can be added to another clamp.
An app can be used independently whereas an extension has to be integrated in a website before it is used.
so you can add other cards, hard drive, drives in general, and other stuff.
A USB extension cable can be used to allow a longer distance between two devices.
.docx The extension docx is used in Word 2007.
For workbooks in Excel 2003, the extension .xls is used.
Excel 2013 uses a .xlsx extension.
it is used to confuse people.
An extension cord holder is used to hold an extension cord. It wraps around the holder, for easy release and withdrawal.
You are referring to the the extension. For Powerpoint it is PPT and XLS is used by Excel.