Do I need a comma?

Hello everyone,

Mass media means forms of periodical dissemination of mass information (print, broadcast and others) which is print, audio, audiovisual and other reports and materials.

Do I need a comma before “which” in the sentence above?

Thank you.

I find it awkward that you are explaining the types of media twice, once in the backets and once in the “which is…” clause. Also, “periodical” is a confusing word to use here because it often means a magazine or journal. I don’t think you need to say this at all. You could say:

“Mass media means forms of dissemination of mass information, including … (list).”

Thank you, Dozy.

“Mass media” refers to the periodical dissemination of information by means of print, audio, and audiovisual reports and materials.

Thank you, Bazza.

Though the sentence confuses us, his actual question was whether or not to use a comma after “which”.

I would say that as long as the meaning of ‘information’ is not restricted, the comma is necessary.

Thank you, T_H_Lawrence.

No need. “Which” is referring back to “Mass media”