What does PRO stand for?

Digital Equipment Corporation (SAUS)

International Proteins Corp. - AMEX symbol (COMM)

Pacific Research Office (CINC)

Pacific Research Onice (SAUS)

Parallel Rod Oscillator

Parents Reaching Out - An association (EA)

Parents Rights Organization (EA)

Particle Reduction Oven

Parts Release Order

Patients' Rights Organization (EA)

Paul Ordini - Air show performer (ASPC)

Pay and Records Office - British military (DMA)

Payments Resource One - Arizona (EARSL)

Peer Review Organization - Medicare

Pen Recorder Output (SAA)

Performing Rights Organization - Formerly, BMI-Canada Ltd. - Canada

Perry, IA - Location identifier - FAA (FAAL)

Personnel Relations Officer - for Shore Stations - Navy

Photographic Reconnaissance Officer (SAUS)

Photonics Research Ontario - Research center (RCD)

Physician Review Organization

Pitch Response Operator

Planned Requirements, Outfitting - Navy (NG)

Planning Resident Order (KSC)

Plant Representative Office (DOMA)

Plant Representative Officer (MCD)

Plastic Repair Optimized (SAUS)

Population Renewal Office (EA)

Precision Risc Organisation (or Organization) (SAUS)

Precision RISC - Reduced Instruction Set Computer Organization

Predictable Research Online - Computer term

Press Officer (SAUS)

Principal Public Library - Library network

Principal Reducing Option

Print Octal (DEN)

Probate

Probation - or Probationer

Probation Services for Adults (PHSD)

Probe - NCIC car model code

Problem Resolution Office - IRS

Procedure (AABC)

Proceed (NAKS)

Pro Craft - NCIC boat manufacturer code (NCIC)

Procurement Research Office - Army

Production Repair Order

Professional

Professional Dental Technologies, Inc. - AMEX symbol (SAG)

Professionally (SAUS)

Professional Racing Organization of America - Later, USCF (EA)

Professional Resellers Organization - Defunct (EA)

Professional Review Organization - Medicare

Proficiency

Proflavine - An antiseptic

Programmable Remote Operation - Computer Devices, Inc.

Programming Online (SAUS)

Program Representative Office (AAGC)

Progressive

Pronation - Medicine

Pronominal - Linguistics (IEL)

Pronoun - Grammar (WGA)

Pronto Explorations Ltd. - Toronto Stock Exchange symbol

Propagation - Military

Propagation Prediction Report (SAA)

Propair, Inc. - Canada - ICAO designator (FAAC)

Propeller Order

Prophylactic (AABC)

Prospect Referral Operation (SAUS)

Prostitute (ADA)

Protector - NCIC firearms make code (NCIC)

Protege - NCIC car model code

Protest

Proved

Providence - Diocesan abbreviation - Rhode Island (TOCD)

Providencia Sign Language - Language code (ETLW)

Province (ROG)

Provost

Provo, UT - Amtrak rail station code

Public Radio Online (SAUS)

Public Record Office - British

Public Records Office - Archives (BAJR)

Public Relations Office - or Officer - Usually military

Public Relations Officer (ADWA)

Puchase Request Order

Prednisone - Also, P, PDN, PR, Pred - Antineoplastic drug, Endocrinology

Proculus - Flourished, 1st century - Authority cited in pre-1607 legal work (DSA)

Proline - Also, P - An amino acid

Prolyl - Biochemistry

Protein

Protest (EBF)

Prothrombin - Factor II - Hematology

Proverbs - Old Testament book (BJA)

Probate (GEAB)

Professional (ODBW)

Proline - An amino acid (DOG)

Provencal - MARC language code - Library of Congress (LCCP)