Definition - What does Theft mean?
Theft is the criminal act of taking another person's property without permission. There are many different types of theft and many different types of property that can be stolen that would constitute as theft. For example, a car getting stolen is theft, jewelry getting stolen is theft, etc. If a person steals the intellectual property of another person, this is also theft.
Justipedia explains Theft
Theft is basically when someone steals something that isn't theirs. Theft is a crime, and is punishable by law. Significant jail time can accompany theft depending on what is stolen. Theft is similar to robbery, but not quite the same. Theft does not necessarily have to occur under threat of force. For example, theft could occur if a person steals a cell phone that another person left on a table at a restaurant.