The research of sociologist William Corsaro suggests that the is the most significant arena in which children and young people acquire cultural knowledge.

peer group

Explanation:

Based on the information provided within the question it can be said that the term that is being mentioned in this scenario is known as a peer group. In the context of sociology, this term refers to a social group of individuals that share various common aspects/traits such as age, interest, background, beliefs, social status, etc. Since the individuals in these groups tend to spend more time together and share more it becomes a significant area for acquiring cultural knowledge from one another.