Courtesy of our friends from the OK Policy Institute:
A block grant is a type of grant program transferring federal funding to states to be used for a broadly defined function. Unlike entitlements, which use a combination of state and federal dollars to administer a range of safety net programs to anyone who qualifies, block grants are capped amounts of federal money. By comparison, entitlement spending allows federal programs to expand or contract in response to need. Because block grants don’t respond to need and commonly do not increase at all year to year or do not increase as quickly as costs, they are in effect deep budget cuts that leavee states on the hook for an increasing share of the funding for basic safety net programs.