A hallway refers to the first room you enter in a house. l could tell you that the coat stand is in the hall, it is unlikely I would say the hallway. Hall can also be used to refer to rooms where meetings take place; The village hall. The assembly hall. The dining hall (in universities). Brocket Hall (name of an old country estate). See hallmark which comes from Goldsmith's Hall in London, they didn't use hallway.
@GemaC Yes it is a synonym, though in general use corridor is used for large industrial buildings and hallway is used for residential dwellings. ln military language you could say that the UN peacekeepers established two safe corridors for medical supplies.