The Free On-line Dictionary of Computing (30 December 2018):

request for proposal

    (RFP) The publication by a prospective software
   purchaser of details of the required system in order to
   attract offers by software developers to supply it.  Software
   development under contract starts with the selection of the
   software developer by the customer.  A request for proposal
   (also called in Britain an "invitation to tender") is the
   beginning of the selection process.

   [Bennatan, E.M., "Software Project Management", 2nd edition,
   McGraw-Hill International, 1992].

   (1995-12-04)