Assault is the attempt or threat to do physical harm to another person.
Battery occurs when there is actual physical contact between the attacker and the victim, though many states no longer differentiate between these two terms. Although assault usually involves one person striking another, merely acting in a threatening manner or instilling fear in another person can be considered an assault.
When the assault involves severe physical injury or the use of a deadly weapon, the more serious charge of
Aggravated Assault can result. Note that you don't actually have to cause physical harm. Even an attempt that involves the threat of serious physical injury or the use of a weapon can be considered aggravated assault.
Violent crimes are taken very seriously and typically involve prison terms and high bail amounts -- or even no bail amounts. The stakes are higher in violent crimes than in almost any other type of criminal charges.
