Here is the definition from the WPI IP Policy:
Generally, an invention, software, or other copyrightable material, will not be considered to have been developed using WPI funds or facilities if:
only a minimal amount of unrestricted funds has been used; and
the Intellectual Property has been developed outside of the assigned area of research of the inventor(s)/author(s) under a research assistantship or sponsored project; and
only a minimal amount of time has been spent using significant WPI facilities or only insignificant facilities and equipment have been utilized (note: use of office, library, machine shop facilities, and of traditional desktop personal computers are examples of facilities and equipment that are not considered significant); and
the development has been made on the personal, unpaid time of the inventor(s)/author.
Using the Gordon Library , the WPI Innovation Studio, or other study locations for your personal intellectual property is not considered significant use.  WPI would still like to hear from you and assist you with your entrepreneurial efforts.