moving from one place to another and back again; "he traveled back and forth between Los Angeles and New York"; "the treetops whipped to and fro in a frightening manner"; "the old man just sat on the porch and rocked back and forth all day"
a military aircraft that drops bombs during flight
a large sandwich made of a long crusty roll split lengthwise and filled with meats and cheese (and tomato and onion and lettuce and condiments); different names are used in different sections of the United States