WOD is an Acronym for "Workout of the day" in Crossfit.
When you arrive at your Crossfit Box your coach will show the workout he has built for the class.
Yes, everyday workout is different! That's one of the AMAZING things in CrossFit. It's never boring.
There are different types of WOD.
First they are different in structure, ie you will find (most common workout types):
AMRAP: As Many Round As Possible. In a given time you'll have to do the more rounds of exercises you can.
For example: AMRAP 10 Minutes: 5 Pullups 10 Pushups 15 Air Squats (this 30 movements are 1 round). You have to repeat this exercises for 10 minutes.
FOR TIME: You have to finish a series of exercises in the less time you can. For Example: FOR TIME: 100 Calories at Rowing Machine, 1 KM Run, 100 Calories at the Row.
TABATA: You have 20 seconds of work and 10 seconds of rest - 8 times for 4 minute workout total.
EMOM: Every minute you have to perform some exercises. You'll be in the game until you perform the given exercises in that minute. For Example: Every minute on the minute for 8 minutes: 5 Back squat and 20 Push-ups
As you can see, starting from the structure, you can find everyday new workouts, new challenges, new goals.
Emanuele