Become part of is a phrase that can be used to describe the process of joining something. The crossword solutions for this phrase are JOIN (4 letters), JOININ (6 letters), and ENTERINTO (9 letters). JOIN is the most basic form of the phrase, while JOININ and ENTERINTO are more specific and imply a more formal process. All three words can be used to describe the same concept, but with varying levels of formality.