The captain term can be edited in the campaign dictionary :

1. Go to campaigns admin panel.
2. Click on Settings tab and Campaign Dictionary tab under it.
3. Find the "Global - Captain Noun item in the list.
4. Click on the item to make changes.
5. Click on Edit button on the pop-up.
6. Make the necessary changes and click Save button.
7. Refresh the site page to see the changes.