I see alot of people talk about procs in regard to their powers and I'm curious... what does that mean?

" I have literally had times when I went five Double Strikes without a PA proc."

"The Shadow gets better procs to compensate for its lower range and smaller Force Pool. "

A proc is an effect which has a chance of happening. Say a power has a 20% of stunning an enemy. That effect is referred to as a "proc"

It's just one of those weird terms. I'm not sure if it's short for something or what.

edit: so when they said " I have literally had times when I went five Double Strikes without a PA proc."

They meant that they used Double Strike 5 times without the bonus effect activating.

A proc is an effect that triggers under certain circumstances, either randomly or in response to another ability.

For instance, my Consular has an ability called Shadow Technique with gives my hits a 25% chance of causing extra damage. When that damage occurs, I'd say Shadow Technique had procced.

In your example, Kinetic Shadows have a skill called particle acceleration that has a 50% chance of triggering when the double strike ability is used. If I hit something with double strike and particle acceleration triggers, that's a PA proc.

It's not an obvious origin. Proc supposedly is short for Programmed Random Occurrence. As above, it's when some effect that has a random chance of occurring, actually occurs.

" I have literally had times when I went five Double Strikes without a PA proc."

Translation: "I've had times when I've used Double Strike five times in a row without triggering the random effect given by my PA ability." (Refers to Particle Acceleration, a Jedi Shadow ability which gives Double Strike a 50% chance to make the next Project attack a critical hit.)

"The Shadow gets better procs to compensate for its lower range and smaller Force Pool. "

Translation: "The Jedi Shadow gets better triggered random effects to compensate for the class's lower attack range and smaller Force Pool for ability use."