A project is a non-trivial, unique goal, that can be described and has to be achieved within a limited amount of time and with limited resources. Examples can range from building a house, developing a company’s new website, or handling a big commission, to things that are larger in scope like major railroad construction or implementing a global toll system. The discipline dedicated to the systematic management of projects is naturally called project management.
The explanation is simple: Most people confuse processes (recurring workflows) with projects (unique and demanding work goals) constantly, one for the other. And it would be one thing if only the public did so, but managers and business owners do so as well. For example, they order the trial of Procesoid (a tool for managing processes) only to write back a few weeks later that they were looking for a project management tool instead.
So it bears repeating once more: Projects are unique and demanding, each of them is different. Processes on the other hand represent recurring tasks and workflows.