D.A.W. means dispense as written i.e., no generic substitution in Prescription
Similar to D.A.W.
A.T.C. - around the clock a.u. - auris utraque - both ears aa - ana - of each ad - ad - up to ad lib. - ad libitum - use as much as one desires; freely admov. - admove - apply agit - agita - stir/shake