Verifier n. : One who, or that which, verifies.

Example:
How does an email address Verifier work?

Taxonomy
driver, Driver Verifier, pool, allocations, verification, IRQL, flags, graphics drivers, registry, tracking, Driver Verifier Manager, Back to the top, Windows drivers, Capabilities, dialogbox, kernel-mode, paged pool, pool memory.

Defination from the web:
Verifier is included in Windows 2000, Windows XP, and Windows Server 2003 to promote stability and reliability; you can use this tool to troubleshoot driver issues. Windows kernel-mode components can cause system corruption or system ...