1) a piece of rubber etc used to stop up a hole, e.g. in a bath; a device used for making a connection with a supply of electric current (plug)
2) a lump of soft material used to keep things apart or in place, or to stop up a hole; a collection (of banknotes, documents etc) folded or rolled together (wad)
to prevent workers from entering a factory etc, e.g. during an argument between management or owners and the workers
block, prevent
