According to lazarus, our first task when faced with a potential stressor is to estimate its severity and to determine whether it is a challenge or threat. this evaluation is referred to as a

   Primary appraisal

Explanation:  Richard Lazarus, a psychologist, gave a theory that stress has a two-way effect or action, a process. The first process is the production of something that makes us stressed by the environment, as well as our reaction to that stressor. This stressor can be an incentive for us because it can mean an opportunity for us, but it can also be a threat. We determine this on the basis of a primary appraisal, that is, assess the possible severity of the stressor in terms of the potential adverse effect, or the positive challenge that stressor may entail.