Halal (حلال) is an Arabic word meaning permitted or lawful. It applies to every part of life, but it is most often used for food.
Halal food must not contain pork, blood, alcohol or other forbidden ingredients, and meat must come from an animal slaughtered according to Islamic law. Most plant, mineral and synthetic ingredients are halal.
The opposite of halal is haram. Things in between, whose status is unclear, are called mushbooh.