Descriptor -

• Real or virtual system - List of word(s), values, equations, classification types, tensors, vector(s), and/or scalar(s) used to describe, define or characterize a real or virtual system, component or object such as a machine (state descriptor) or reference coordinate system (origin and axes descriptors). A descriptor can incorporate other state descriptors, that is, a machine descriptor can be a combination of each component's state descriptor along with descriptors that define the interrelation of the components (such as relative locations and velocities etc.).
• Computer file systems - a small nonnegative integer used to specify (point to) an input or output location which is used by the computer in place of the name of a file.