What is VT?

Some articles on vt:

List Of Intel Core I7 Microprocessors - Mobile Processors - Sandy Bridge Microarchitecture - "Sandy Bridge (Quad-Core)" (32 Nm)
... Intel 64, XD bit (an NX bit implementation), TXT, Intel VT-x, Intel VT-d, Hyper-threading, Turbo Boost, AES-NI, Smart Cache ... Core i7-2635QM, Core i7-2670QM, Core i7-2675QM do not support TXT and Intel VT-d ...