JODAN - This means upper level, so if the Instructor says "Jodan Oi-Tsuki" You would perform a lunge punch to the head.
CHUDAN - Means middle level.
GEDAN - Means lower level
KIAI - This means shout. Don't worry, this part is a bit scary, but it'll get easier!
HAJIME - Begin
YAMAE - Stop
MAWATE - Turn. If your Instructor calls this, then they want you to turn and face the other direction, although there is a certain way to turn, which they will teach you!
REI - Bow
SEIZAI - This means the Instructor want you to kneel down. Usually done at the beginning and end of a class.
MOKUSO - Meditate. This is done at the end of a karate class.