What is the difference between assault and battery in Florida?

They're separate offenses and the distinction matters.

Assault is an intentional, unlawful threat by word or act to do violence to another, coupled with an apparent ability to do it, creating a well-founded fear that violence is imminent. No contact required — the threat is the offense.

Battery is actually and intentionally touching or striking another person against their will, or intentionally causing bodily harm. No injury is required. A push, a grab, a shove, or spitting can all qualify.

That last point surprises people constantly. "I barely touched him" is not a defense to battery; it's a description of battery.

Simple assault is a second-degree misdemeanor. Simple battery is a first-degree misdemeanor, with enhancement for a prior battery conviction.

Both escalate substantially with aggravating factors — a weapon, great bodily harm, or the status of the person involved.