Best Answer: A certified letter is sent by a person or a business when they want to mail important information and be sure that it was received. It's not usually a good thing. Collection agencies send them, people involved in legal cases send them, etc... certified letter is one where the post office ensures that the letter is only delivered to the person it was addressed to, and records his signature.
For other uses, see MS. A Master of Science degree (Latin: Magister Scientiae; abbreviated MS, MSc, MSci, ScM or SciM with or without punctuation) is a type of master's degree awarded by universities in many countries. The degree is usually contrasted with the Master of Arts degree.
Abbreviate a master's of arts in education degree as M.A. or M.A.Ed.. The degree awarded tells you which abbreviation to use. If it says master's of arts -- use M.A. If it says master's of arts in education -- use M.A.Ed. Harvard and M.I.T. use A.M. to abbreviate the master's of arts degree.