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.