What is considered a publication?

Okay I read on here about bunch of middle author, co-author publications. But what is considered a publication? Does it have to be an academic article published in a well known journal like, Journal of Autoimmunity? or Journal of American Medical Association, or Journal of Immunology? Or can they be publications in smaller journals. At my university they have a program called Excellence in Research where if you are awarded the "excellence in research" your article that is based... What is considered a publication?
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Source Type: forums