Kosher has roots in Hebrew signifying that which is fit or appropriate. In the current context the word kosher generally represents foods and beverages as being compliant with religious dietary laws of the Jews.
A food product or beverage can apply the kosher label if each ingredient used therein, food additives, colorants, preservatives, process; equipment's and methods are fully compliant with Kosher specifications. A kosher auditor approves the production process before the manufacturer can apply the Kosher logo. Laws are so strict that if equipment's used to manufacture non-kosher foods are used for kosher foods then that specific food can no longer carry the kosher label.