Personal Access Communications System 
Picture Archiving and Communication Sy… 
Picture Archiving and Communications S… 
Pointing and Attitude Control System 
Programmable Automation Controllers 
Physics and Astronomy Classification S… 
Pan American Climate Studies 
Particle Analysis Cameras of Shuttle 
Payload Access Control System 
picture archival and communications sy… 
Picture Archiving and Communications S… 
premature atrial contractions 
Payload Actuation and Control System 
Personal Access Communications Service… 
Photodetector Array Camera and Spectro… 
Picture archive and communication syst… 
picture archiving and communication sy… 
picture archiving communication system 
Polar Acquisition and Control Subsyste… 
polycyclic aromatic compounds 
Programmable Armament Control Set 
Programme Advisory Committees 
P1 artificial chromosomes 
P1-based artificial chromosomes 
P1-derived artificial chromosomes 
Pacific Area Cataloging Seminar 
Pacific Area Communications System 
PACIFIC CONSTRUCTION CORP. 
partial anterior circulation syndrome 
Patch Administration Control System