An appropriation bill is a type of legislative measure that allocates funds for specific purposes. It is also known as an “expenditure bill” or “spending bill”. An appropriation bill authorizes the government to spend money on various programs, projects and activities by designating the amount of funding required for each purpose. This type of bill typically covers a range of expenses including salaries, operating costs, equipment purchases, research grants, etc., within a specific department or agency. The process of approving an appropriation bill is usually tied to the budget cycle and must be passed by both houses of Congress before it can be signed into law by the President.