News media and others constantly misuse the words larceny, burglary, and robbery. As a word maven and former FBI agent/attorney, this annoys me. Legal definitions vary from state to state and country to country, but these simple definitions should help clear up some confusion.
Larceny is just another word for theft or stealing. It can take many forms, such as shoplifting, fraud, stealing a bike from a rack, keeping something valuable that you found, and so forth. Typically it is a misdemeanor, although it can be a felony if enough money is involved.
Burglary is the entering of a dwelling for the purpose of committing a crime therein. In common law it was limited to a dwelling, i.e. somewhere people live, but modern statutes typically include businesses, government offices, or any building to which the burglar does not have legal access. Usually there are several classes or degrees of burglary, such as of a dwelling, an occupied building, or while armed. Note that it does not require theft. The intent to commit any crime inside, such as rape or vandalism, is all that is required. It doesn’t even require that the crime be committed, only that the person intends to do so at the time he or she entered. This is a felony and is generally categorized as a violent crime, more serious than mere theft. This is because the entering creates a dangerous situation, the potential for violence. A homeowner or store owner or even a sales clerk may confront the burglar or vice versa. A shootout, fistfight, or other violent encounter may very well ensue. Mike Wallace once confronted a prosecutor as to why he sent a third strike burglar to prison for life by charging it as a felony when “all he did was steal a bicycle.” No, that’s not all he did, moron. He entered a closed garage to steal it. What if the homeowner had walked into the garage just then? Would the burglar have grabbed a crowbar or screwdriver and killed him? Stealing the bike was by itself nonviolent, but the burglar had a violent crime as one of his first two strikes, so he was prone to violence and this lethal scenario is all too possible. Stealing a bicycle from an outdoor rack in a public place is bad, but not nearly as likely to cause violence. Shoplifting can also be burglary, although it is also possible to steal from an outdoor display, which would be larceny. That’s why the term shoplifting isn’t generally used in criminal codes.
Robbery is the unlawful taking from another by force or threat of force. This is the most serious of the three crimes because of the force used and the fact that another person, a victim, is present. The chance of escalation to a deadly situation is the highest and most obvious here. Michael Brown, for example, committed robbery. The now-famous store video showed him clearly shoving the clerk (store owner?) who was trying to stop him from leaving without paying for the cigars. When the clerk tried a second time, 6’8″ Brown turned and started back at the man in a threatening manner. I don’t know what Missouri’s statutes say, but at common law this would be a robbery, a felony, for which the penalty would probably be death by hanging.