Homing in on' is a phrase that describes the act of focusing on a particular target or goal. It is often used to describe the process of finding something or someone, such as a lost item or a missing person. The term 'zeroing in on' is a synonym for homing in on, and it implies that the target is being approached with precision and accuracy. Both terms are used to describe the process of narrowing down a search until the desired result is achieved.