fraught with danger; "dangerous waters"; "a parlous journey on stormy seas"; "a perilous voyage across the Atlantic in a small boat"; "the precarious life of an undersea diver"; "dangerous surgery followed by a touch-and-go recovery"
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"
at the same time but in another place; "meanwhile, back at the ranch..."
the branch of physics concerned with electromagnetic phenomena
magnetism produced by an electric current; "electromagnetism was discovered when it was observed that a copper wire carrying an electric current can magnetize pieces of iron or steel near it"