| Terms | Definitions |
| Cluster designation or cluster differentiation (CD) | A group of antibodies that recognize the same antigen. |
| Fluorochrome (fluorophore) | A fluorescent marker that is excited by light of one wavelength (generated by the flow cytometer's laser) and emits light of a different wavelength (fluorescent light). |
| Gate | A boundary is set around a subset of data points to segregate those events for analysis or exclude other events from the analysis. |
| Immunofluorescence | Fluorescent expression of immune reactions between antigens and antibodies. |
| Monoclonal antibody (MoAb) | An antibody is produced from a single clone of cells and, therefore, has high purity and reproducibility. A monoclonal antibody used in flow cytometry is directed against a single antigen. For example, the CD2 MoAb will bind to the CD2 antigen on the cell surface of a T cell. |
