The phrase "certain radius" refers to a specific distance from a center point. It means a particular measurement from the center, usually in a circular shape. Full definition
Besides that, location results should also be sorted in terms of their proximity and relevance, within a certain radius of the customer. (arcadier.com)
Fourth, each black congregation should assess the needs of its constituents within a certain radius of the church. (religion-online.org)
Additionally, many faiths do not require one to live within a certain radius of a place of worship. (religion.blogs.cnn.com)