It is bullying that happens in a workplace, however the method of the bullying is much different to what you're usual idea of bullying would be.
It can involve multiple perpetrators attacking the victim in the one workplace, or it could be caused by one perpetrator at each place that the victim works at in their life.
Often workplace bullying doesn't end at one place of work, but continues by other perpetrators at the victim's subsequent workplaces.
One method is to make the victim feel as though people are spreading malicious gossip about the victim when they are not.
Another tactic is to undermine work performance by deliberately withholding information vital for effective work performance.
Sometimes the bullying may in the form of ostracism.
Jim was the victim of workplace bullying, which, due to its clandestine nature, nobody except him and his bullies were aware of.
Sarah was a victim of workplace bullying when she was ostracized.
The many short stints of work listed on Mike's resume were a result of workplace bullying.
The workplace bullying was carried across from one employer to another, when Frank lost his jobs.
Workplace bullying was part of the gang stalking that Mary endured.