An intervention is strategy to produce change among individuals or entire population.
Is the definition of intervention correct ?
Do you mean a research setup with two groups: a treated group and a non-treated controlgroup? In this case, I'd call the treatment an
intervention for the treatment group.
For example in medicine studies, the intervention could be giving certain medicine to the treatment group while not influencing the control group (e.g. by giving them placebos).
Social Science Context
In social science, an intervention is the implementation of a change strategy which can be applied on individual, group or any kind of societal level. Read more about it: Source