A bill is a proposal for new legislation that is introduced in either chamber of Congress (House of Representatives or Senate). It must be passed by both chambers and signed by the President (or overridden) in order to become law.
Related terms
Law: A law is a rule established by government through legislation.
Committee: A committee is a group within Congress that specializes in specific areas such as finance or foreign policy, and reviews bills before they are voted on.
Amendment: An amendment is a change or addition made to a bill, law, or constitution.