The following abbreviations share two unusual qualities. Can you determine what they are?

1. MA
2. OK
3. JD
4. MP
5. PA
6. DC

Answers:

Each abbreviation can stand for at least two different things:

1. MA - Massachusetts - Master of Arts
2. OK - Oklahoma - Okay
3. JD - Juris Doctor - Juvenile delinquent
4. MP - Military Police - Member of Parliament
5. PA - Pennsylvania - Public address
6. DC - District of Columbia - Direct current - Doctor of Chiropractic 

AND

Each abbreviation can be reversed to form another abbreviation:

1. MA - AM   (before noon)
2. OK - KO    (knock out)
3. JD - DJ       (disc jockey)
4. MP - PM     (after noon)
5. PA - AP       (advanced placement)
6. DC - CD      (compact disc or certificate of deposit)