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definitions

p.o.

  1. (in prescriptions) by mouth.

Origin of p.o.

From the Latin word per ōs

P.O.

  1. parole officer.
  2. petty officer.
  3. postal (money) order.
  4. post office.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018