A response variable in statistics is a variable that represents the outcome of an experiment or some other study.
A response variable is a measurement recorded during an experimental procedure. It usually means any variable whose values are being examined under different conditions, and can be thought of as something measured directly by the researcher, such as perceived pain levels with each shock level on a device designed to measure pain sensitivity. This measurement can also be obtained through indirectly observing variables such as heart rate, protein levels in blood cells, etc. In fact it could even refer to something that’s not easily measurable by someone other than the researcher like how pleasant researchers perceive their day-to-day actions to be on average while conducting research work; for this situation it would simply be a subjective self-report of the researcher.
In regression analysis, the response variable is the variable whose values are predicted by the model.