Process is a series or steps of actions. Process can be referred to an action being executed or it can also refer to sequence of interdependent and linked procedures which consumes some resources to convert inputs into outputs. These are the standard definitions which are widely accepted but the meaning may change in the field of computing. In fact, meaning of process differs according to context.

Process definition (noun)
In computer field, process is an instance of a computer program that is being executed by the CPU.
Process definition (verb)
The action performed by CPU for converting data into information is called process.

A program or component of OS called processor manager, manages the process execution. A process is also called as the image of the executable machine code associated with a program. A process may also have various process states like waiting, ready, blocked etc.