Use the adverb meanwhile to mean "at the same time." For example, you might have a great evening at the bowling alley, but meanwhile, your parents are home wondering why you never showed up for dinner.
The word meanwhile is handy when you’re telling a story because sometimes it’s funny to realize what two things are happening at the same time. You might be frantically searching for your cat, meanwhile, he's lounging under your bed. Meanwhile can also refer to the time before something happens, as in "I have an interview in an hour, but meanwhile I'm going to take a nap." The word meanwhile is rooted in mean, with its meaning of "middle" or "intermediate."