FACS is an acronym that stands for fluorescence-activated cell sorting, a technique used in biology and medicine to separate and analyze specific cells based on their fluorescence properties. Some synonyms for FACS include flow cytometry, fluorescent cell sorting, and fluorescence-activated sorting. All of these terms refer to the same basic technique of identifying and separating cells based on their fluorescence signature. Other related terms include cell surface markers, which are specific proteins or molecules on the surface of cells that can be detected and sorted using FACS technology. Overall, FACS is an important tool in biomedicine for understanding the properties and behavior of cells, and its various synonyms all refer to the same basic technique.