#1 open up v. cause to open or to become open; "Mary opened the car door". wn #2 open up v. become available; "an opportunity opened up". wn #3 open up v. make available; "This opens up new possibilities". wn #4 open up v. open up an area or prepare a way; "She pioneered a graduate program for women students". wn #5 open up v. start to operate or function or cause to start operating or functioning; "open a business". wn