Her dream of competing in the Olympics became a 'reality'. [=she competed in the Olympics, as she had dreamed of doing]
He was starting to think he was infallible, so the criticism from his boss served as a 'reality check'.
Her friends gave her a 'reality check' about her boyfriend. [=told her the truth about her boyfriend]
(..) They don't actually come into the dream. They just design the levels and teach them to the dreamers. That's all. Design it yourself. Mal won't let me. Come back to reality, Dom. - Please. - Reality. Those kids, your grandchildren... ...they're waiting for their father to come back home. That's their reality. And this job, this last job, that's how I get there. I would not be standing here if I knew any other way. I need an architect (..)2010 Inception