Hatha (pronounced huh-tuh) has multiple meanings. In the modern context, the word is generally used to describe classes that are alignment-based and non-flowing. Even more generally, the word hatha describes any kind of yoga practice that emphasizes yoga asana, or postures.
Karma is one of the yoga words that many of us are familiar with. The popular understanding of karma is the adage, "what goes around, comes around." In other words, every action has a consequence, and if it's a bad action, you'll get your comeuppance.