This is completely unacceptable in many ways, including legally.
While only a court can definitively pronounce on what is harassment, this is virtually certain to fall within that category.
You should immediately take this up with the company. Start with your boss, but if he does nothing (or he is one of the people involved) go to HR. Tell them what has happened, tell them you believe it is both harassement and workplace bullying. Tell them you want to file a formal complaint. If you are in a union or professional association then also get their advice (preferably before going to HR). If race, gender, sexuality or religion are involved then tell HR that as well. The combination of those will virtually force them to take action. The company has a legal responsibility to prevent this kind of thing. If they are the kind of company that won't do that, despite legal responsibilities, you are definitely better off elsewhere.
You should expect that disciplinary action is taken against the people involved, and that HR tells you that they have done something and that it will not happen again. If there is any repetition, or any attempt to punish you for the report, then tell HR immediately.
If HR refuses to take effective action you have the option of getting a lawyer and seeing if there is a case for suing them. This is potentially expensive, but if you are in a union then the union will often bear the legal costs for you. You might find that the threat makes them clean up their act. But if it gets to that point you are wise to have the option of another job to go to. If you do not want to take legal action then quitting is the only option.
NOTE: The entire above answer is written on the assumption that you have done nothing to provoke this reaction. If you have yourself assaulted, harassed or bullied you co-workers, or made comments or espoused views that could be considered hateful or discriminatory, then any escalation of this is probably going to result in disciplinary action for yourself.