Final answer:
The patient took penicillin orally three times a day for five days straight, which is what the abbreviation 'Pt. took PCN TID PO for 5 days' in a PCR signifies.
Step-by-step explanation:
The notation "Pt. took PCN TID PO for 5 days" in a prehospital care report (PCR) means that the patient took penicillin orally three times a day for five consecutive days. In medical abbreviation, PCN stands for penicillin, TID means three times a day (ter in die in Latin), and PO refers to the route of administration being oral (by mouth). Therefore, the interpretation of this entry is that Penicillin was taken orally three times a day for five days straight.