What does PSIS stand for?

Permanent Secretaries Committee on the Intelligence Services (SAUS)

Persists - Telegraphy (PCTE)

Plastic Surgery Information Service (SAUS)

Posterior Sacroiliac Spine - Anatomy (DAVI)

Posterior Superior Iliac Spine - Medicine (STED)

Pounds per Square Inch per Second

Pounds per Square Inch Sealed (NASA)

Programme for Strategic and International Security Studies - Switzerland (PDAA)

Programming Systems Information System (SAUS)

Pounds per Square Inch Sealed (NAKS)