Definitions of Pa:

• noun:   a unit of pressure equal to one newton per square meter
• noun:   a Mid-Atlantic state; one of the original 13 colonies
• noun:   a short-lived radioactive metallic element formed from uranium and disintegrating into actinium and then into lead
• noun:   an informal term for a father; probably derived from baby talk
• noun:   an electronic amplification system used as a communication system in public areas
• name:  A female given name (rare: 1 in 100000 females; popularity rank in the U.S.: #3244)
• name:  A surname (very rare: popularity rank in the U.S.: #55092)