1 : to occur, fall, or come between points of time or events <only six months intervened between their marriage and divorce>
2 : to enter or appear as an irrelevant or extraneous feature or circumstance <it’s business as usual until a crisis intervenes>
3 a : to come in or between by way of hindrance or modification <intervene to stop a fight> b : to interfere with the outcome or course especially of a condition or process (as to prevent harm or improve functioning)
4 : to occur or lie between two things
5 a : to become a third party to a legal proceeding begun by others for the protection of an alleged interest b : to interfere usually by force or threat of force in another nation’s internal affairs especially to compel or prevent an action