v.1. To become wider: The river opens out as it heads toward the bay.
2. To unfold or expand so that inner parts are displayed; spread out: The couch opened out into a bed.
3. To unfold or expand something; spread something out: I opened the couch out into a bed. Let's open out the model to see how it works.
4. open out on To be a passage or opening to some larger external space: After we remodel, the living room will open out on to the kitchen.