When you create a new run of a workflow, you can assign the run to a user or users in your account. These people are referred to as Participants on the Run as you can see on the “new run” page.
We use the word Participant to differentiate with the word we use for when you assign steps within a run to those participants.
Step level assignments are referred to as Assignments as you’d expect. So when you go to the Runs list page, you can see the participants on each run. And when you go to your Inbox, you can view both your runs and your step assignments