Give a definition of Cohort in Google Analytics?

A cohort is a collection of people who have something in common that is in this report indicated by an Analytics dimension. For instance, a cohort is made up of all users who have the same acquisition date. You may isolate and examine cohort behaviour using the Cohort Analysis report. See cohort statistics in this article.

The technique of grouping users according to specific criteria and tracking how their behaviour evolves over time is known as cohort analysis. You can learn how your digital marketing efforts effect key performance measures, such as conversion and retention rates, churn rates, revenue per user, CLV, ROI, CAC, etc., by using this type of analysis.