“EMOM” stands for Every Minute On the Minute, which is when you begin a specified number of repetitions of some movements or exercises at the start of one minute and then rest for whatever time you have left until the top of the next minute.
“EMOM 12 min” means: every minute on the minute for 12 minutes, do the specified exercises.
EMOM workouts are usually short, 10-20 minutes long (but can be shorter or longer), and are typically designed to allow for some rest before the top of each work interval. These built-in work and rest periods make EMOM a form of interval workout. They can be great for practicing pacing and working on conditioning, but are also a good format for strength training, to force attempts of a lift on a specified cadence.
EMOMs can be every minute, every 2 minutes, every 3 minutes, etc. For example, “E2MOM” means each 2 minutes, where you have 2 minutes to perform some amount of work. This can also be written as EOMOM (every other minute on the minute). “E3MOM” means each 3 minutes, etc.
Depending on the workout an EMOM workout may be simply scored as the total number of full rounds completed, or the weight used.