A Visa is a travel document that is issued by a consulate to someone who wishes to visit the United States. A Visa is placed in your passport and shows the Visa Type, such as F-1, E-2 or H-1B and it allows a person to enter the United States at a port of entry (e.g. an airport).
An immigration status refers to the classification under which the person entered the United States (F-1, E-2, H-1B, etc.) and the length of time the person is permitted to stay in the United States. The status is based on regulations and is referred to a set of rights and responsibilities an individual has toward the government.
Expiration of Visa vs. Expiration of Status:
A Visa is only an entry document and can expire while you are in the U.S. If your Visa expires while you are legally present in the U.S, as long as your status is still valid and you continue to follow all immigration regulations, you can continue to remain in the U.S. Your status does not end upon expiration of your travel document.