A dollar that is of smaller value relative to foreign currencies. A weak dollar exchanges for fewer units of other currencies compared with the units for which it could have been exchanged in the past. A weak dollar tends to help U.S. firms that rely heavily on foreign sales because the firms' products will cost less in terms of the foreign currencies. A weak dollar hurts consumers of foreign goods because these goods cost more in terms of U.S. dollars. Compare strong dollar. See also exchange rate.