A blade server is a stripped down server computer with a modular design

Modular design

Modular design, or "modularity in design" is an approach that subdivides a system into smaller parts that can be independently created and then used in different systems to drive multiple functionalities...

 optimized to minimize the use of physical space and energy. Whereas a standard rack-mount

19-inch rack

A 19-inch rack is a standardized frame or enclosure for mounting multiple equipment modules. Each module has a front panel that is wide, including edges or ears that protrude on each side which allow the module to be fastened to the rack frame with screws.-Overview and history:Equipment designed...

 server can function with (at least) a power cord and network cable, blade servers have many components removed to save space, minimize power consumption and other considerations, while still having all the functional components to be considered a computer

Computer

A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...

.