International Space Station 
Institute for Standardization of Serbi… 
Imaging Science Subsystem 
Information Systems Security 
Internet Security Systems 
Information System Security 
Input Shaft Speed 
I said so 
Inertial Sensor System 
Information Systems 
Integrated Sounding System 
Intelligence Systems Secretariat 
Interim Supply Support 
Internet Security Scanner 
Image Stabilization System 
In School Suspension 
initial send sequence 
Integrated Signaling System 
Integrated Surveillance Systems 
Inter-Satellite Service 
ion scattering spectroscopy 
Issue 
idiopathic short stature 
I'm So Sure 
Individual Support Services 
Information Security Solutions 
Information Security Specialist 
Information Systems Services 
Information Sysytems Staff 
injury severity score