The initials apr stands for annual percentage rate. Used when borrowing money , basically the interest that will be tacked on to the money your borrow.
They stand for Doctor of Osteopathic Medicine, which is a professional degree of physicians and surgeons. It is a bit different than an M.D. in the sense that D.O.'s are taught physical manipulation,...
Usually it stands for Annual Percentage Rate (used to calculate the amount of interest charged on the balance of a credit card or loan). If that doen't make sense in relation to where you saw it then...