Social Norm

Norms are usually the rules and regulations that groups of people live by or standards of behavior. The term "norms" covers an exceptionally wide range of behavior. Sociologist’s defined norms as a set of rules developed by a group of people that specify how they must, should, may, should not, and must not behave in various circumstances. Norms are the social rules that control behavior in the community at large. Norms are learned as an individual grows in a given environment. Some norms are classified by a group of individuals and societies as crucial to the society and hence govern them.
For example, for safety reasons, if A&P students are required to always wear a lab coat for practical and a student refuses to bring her lab coat to class. And the instructor penalizes her by denying her access to the class for two consecutive weeks.
Sanctions, on the other hand, are mechanisms of social control.
Individuals or groups upon other individuals without the involvement of the legal system impose negative sanctions. They include shunning boycotts, scornful looks, gossip, satire, laughing at others; threats, name-calling and other actions are forms of informal sanctioning.
An example: A lot of people have a perception of Wal-Mart not treating their employees right and because of these most customers who object to this practice organize a boycott against Wal-Mart. In this case, Wal-Mart loses customers, sales, and income as a result of this.
Another example: Is the A&P instructor ignores the students who refused to bring a lab coat to lab practical and allowing the punishment to hold. In this instance, since the student will miss two consecutive labs, he or she has the tendency to fail the class.

References

• https://www.thoughtco.com/sanction-definition-3026570
• Janowitz, Morris, and James Burk. 1991. On Social Organization and Social Control. Chicago: University of Chicago