Plant (Control Systems)
In control systems, a plant can be considered synonymous with the word "system". It is something that takes an input and modifies it to get the desired output.
A plant in control theory is the combination of process and actuator. A plant is often referred to with a transfer function (commonly in the s-domain) which indicates the relation between an input signal and the output signal of a system without feedback, commonly determined by physical properties of the system.