I have not heard anyone say the word "shield" or use one in any pvp videos. Do you not use them in pvp or something?

It's a passive. You wear a shield generator and it has a chance to absorb a percentage of damage on incoming attacks. It produces a brief deflection animation when something is blocked, I believe. (Mechanically it works similar to the light saber deflection mechanic for the melee classes, but with a different animation). Shield chance and absorb percentage can both be buffed by talents, stats, and the gennie you wear. There is also a short-term ability called Reactive Shield that you can pop which reduces damage by 25% for 12 seconds maxed out; I think that one appears as a bluish dome around you while it's running.

It's a passive. You wear a shield generator and it has a chance to absorb a percentage of damage on incoming attacks. It produces a brief deflection animation when something is blocked, I believe. (Mechanically it works similar to the light saber deflection mechanic for the melee classes, but with a different animation). Shield chance and absorb percentage can both be buffed by talents, stats, and the gennie you wear. There is also a short-term ability called Reactive Shield that you can pop which reduces damage by 25% for 12 seconds maxed out; I think that one appears as a bluish dome around you while it's running.

Of course he's right, and there is also the sage damage block spell which they can use on allies (Think power word shield). This is what you will think of when you think of shield in pvp because, as heezdedjim stated, normal shield is just another mechanic akin to dodge, albeit a mechanic we rely on heavily.