EMD stands for Earnest Money Deposite. In college admission perspective it can be called as the security deposite that you pay before admission. The word earnest means "serious". So this amount of money is deposited to ensure that the applicant is responsibly interested in further procedure.

This term is mostly used in management quota seats as the amount to be paid is very high and security deposite enaures that the applicant is genuine.

Hope this helps!