A beheaded stream is a stream or river that has been diverted or cut off from its original source due to geological processes such as faulting, volcanic activity, or glaciation. This can result in a dry riverbed or a stream with reduced flow. Beheaded streams provide evidence of past geological events and are studied to understand landscape evolution and the effects of tectonic activity.
Reference: Summerfield, M. A. (1991). Global Geomorphology. Longman Scientific & Technical.