BuddyPress.org

@ajc88
I just did this for a website I’m doing. The easiest way is to make a language file with the changes. See this page on the documentation to do it: https://codex.buddypress.org/how-to-guides/customizing-labels-messages-and-urls/

Basically, you change everywhere that it says group to whatever you want the name to be.

If you just want the link to “Groups” page to be something different, you could do a child theme (see https://codex.buddypress.org/how-to-guides/building-a-buddypress-child-theme/) and change the file header.php where it adds the group navigation link. However, it will still say group everywhere else you go.