At the Network level, go to Network Settings > General > Scroll down until you reach the "Other Settings" section > Role Naming.
From there, you can drop down and select one of the pre-chosen names or create a custom name for each of the roles.
If you choose the custom name then you will be able to choose how you would like it to appear as a singular name, article name, plural name or possessive plural name.
The roles will show on each of the profiles, like below:
You can also change the names of roles at the Space level by going to the Space, clicking the gear icon > Details > The Small Stuff > Role Naming.
If you have the Table of Contents feature enabled in a Space, then each role in that Space can now have a custom name. They will appear as separate names on the About page for the Space as well.
For example, in this Space we named Hosts Coaches and Moderators, Admins.
To learn more about Space Host and Space Moderator roles, check out this article.
You will have the option of making the roles the same as the network, choosing the ones from the drop down menu, or creating your own!