Single-cell refers to the study and analysis of individual cells, which allows scientists to understand the unique characteristics and functions of each cell type. This approach is crucial in fields like genetics, immunology, and cancer research, as it provides insights into cellular diversity and behavior that are often masked in bulk analyses. Techniques such as single-cell RNA sequencing enable researchers to examine gene expression at the single-cell level, revealing how cells respond to different conditions. This information can lead to advancements in personalized medicine and targeted therapies, improving treatment outcomes for various diseases.