Functional Near-Infrared Spectroscopy (fNIRS) is a technique widely used in neuroscience research to examine brain function. However, there are various alternate terms used to refer to fNIRS, including Optical Brain Imaging, Near-Infrared Imaging, and Cerebral Optical Topography. Optical Brain Imaging underscores the core technology behind fNIRS, which is the detection of light absorbed and scattered by biological tissue. Cerebral Optical Topography emphasizes the topographical imaging capabilities of fNIRS, which allows for the noninvasive mapping of brain activity. Other related terms used interchangeably include NIRS, fNIR, and NIRs. These synonyms of fNIRS are useful for identifying the same technology in different scientific papers and studies.