What's he mean by "focus group?"

Native speaker’s answer
Rebecca
In research or discussion terms, "focus groups" are groups of people that meet to participate in a guided (with a leader) discussion about a specific topic. These groups are usually quite diverse (in terms of age, religion, ethnicity, and so on) to get more opinions and better represent real diversity in society. Ex: I participated in a focus group on Millennial opinions about the pandemic. Ex: The group of 100 interviewees were divided into 10 focus groups.