Curcumin is the yellow pigment associated with the curry spice, Turmeric, and to a lesser extent Ginger. It is a small molecule that is the prototypical 'curcuminoid', and has effects similar to other polyphenols but unique in a way as it is a different class of polyphenol (relative to the other classes of 'flavonoid', 'stilbene', etc.)
The most simple definition of virtualization is the creating of a virtual version of something. This could be an operating system, server, storage device, or other resources. One common example would be someone who has divided their hard drive into multiple partitions. Uses.
Cloud is not just virtualization. Just throwing a hypervisor on a server is not private cloud computing. While virtualization is a key component to cloud computing, it is not a cloud by itself. Virtualization technology allows organizations to pool and allocate resources, which are part of NIST's definition.