CRO, or Conversion Rate Optimization, is the process of increasing the percentage of website visitors who take a desired action—such as making a purchase, filling out a form, or subscribing to a service. It involves analyzing user behavior, testing different versions of web pages or elements (like buttons, headlines, or layouts), and using data-driven strategies to improve overall performance. CRO aims to make the most of existing traffic by turning more visitors into customers, thereby maximizing return on investment without necessarily increasing marketing spend.