Change 'Members' to 'custom text' in menus

Hello,
I want to change ‘Members’ to ‘Council’ in all menu displays and search menus. Pls, how to do it? Is it in php code - or in lang file?

Most of the text displays are probably in members.lang. You will also find the term used in other.lang, users.lang, admin.lang, boxes.lang, categories.lang, main;lang, etc.