What does RIO stand for?

RADAR Intercept Officer - Navy

RADAR-Intercept Operator

Radio Information Office - National Audience Board (NTCM)

Radio Intercept Officer (MCD)

Ramus Infraorbitalis - Anatomy

Reconfiguration of Input/Output - Computer science (VLIE)

Red Iron Oxide (UWER)

Redistributed Internet Objects (SAUS)

Regimental Intelligence Officer (SAUS)

Registry of Italian Oddities (EA)

Religious Index One: Periodicals

Relocatable Input/Output

Remain Intact Organization (EA)

Remote Input/Output (NITA)

Reporting In and Out - Military

Research Industry Office (MCD)

Reshaping the International Order - Title of Club of Rome report

Resident Inspector Office - Coast Guard

Resident Inspector of Ordnance (AAG)

Resin-in-Pulp - Process for uranium ore treatment (IIA)

Resume Input/Output (SAUS)

Retail Issue Outlets (NG)

Reviewing the International Order (SAUS)

Rhodesian Information Office (SAUS)

Ride-It-Out

Right Inferior Oblique - Projection - Radiology (DAVI)

Rio (automobile) - NCIC car model code

Rio De Janeiro - Brazil - Airport symbol (OAG)

Rio Grant - Caja Del Rio - New Mexico - Seismograph station code, US Geological Survey - Closed (SEIS)

Rio Sierra Silver - Vancouver Stock Exchange symbol

Roll in Only (NITA)

Roll-in-Out (SAUS)

Royal International Optical Corp. - NYSE symbol (COMM)

Royal Italian Opera

The Remain Intact "ORGAN"ization (EA)