Meanwhile means while a particular thing is happening. Brush the aubergines with oil, add salt and pepper, and bake till soft. Meanwhile, heat the remaining oil in a heavy pan Kate turned to beckon Peter across from the car, but Bill waved him back, meanwhile pushing Kate inside
Meanwhile means in the period of time between two events. You needn't worry; I'll be ready to greet them. Meanwhile I'm off to discuss the Fowler's party with Felix
during the intervening time; "meanwhile I will not think about the problem"; "meantime he was attentive to his other interests"; "in the meantime the police were notified"
You use meanwhile to introduce a different aspect of a particular situation, especially one that is completely opposite to the one previously mentioned. He had always found his wife's mother a bit annoying. The mother-daughter relationship, meanwhile, was close