what is 301 redirect in seo in plain english?

permanent forwarding. someone requests old-page, the server says "that's moved for good, it's here now" and sends them to new-page. google follows it and transfers most of the old page's credit to the new one. use it when you rename, delete, or merge pages, move to https, or change domain. the 302 version means temporary and doesn't pass things on the same way. one thing to avoid: chains, where a redirects to b which redirects to c, just point a straight at c.