What is a mezzanine card?

• A. A detachable storage drive useful for mobile systems.
• B. An external USB accessory for peripheral expansion.
• C. Low-profile, board-to-board module used in blades or dense servers.
• D. A network interface card that remains in the chassis.

Answer: (C)

A mezzanine card is a compact, low-profile board-to-board expansion module designed for blades and dense servers. It plugs into dedicated connectors on the blade’s backplane, providing additional I/O (such as network or storage interfaces) without occupying a full-sized PCIe slot or sticking out of the chassis. This internal, blade-focused form factor enables high-density configurations where space is limited. It’s not a detachable storage drive, not an external USB accessory, and not simply a NIC that sits in a traditional chassis slot—the mezzanine card is an internal, board-to-board module specific to blade/server architectures.