The term 'PART OF (THE PLAN)' can be broken down into four crossword solutions: STEP (4 letters), PHASE (5 letters), ONBOARD (7 letters), and INON (4 letters). STEP is a noun that refers to a movement or action taken in order to achieve a goal. PHASE is a noun that refers to a distinct period or stage in a process of change or development. ONBOARD is an adjective that describes the act of being included in a plan or project. INON is an acronym for 'In On, ' which means to be aware of or involved in something. Together, these four words refer to the different stages and components of a plan that must be taken in order to achieve a desired outcome.