A redirect is a way to send both users and search engines to a different URL than the one they originally requested.
Types of redirects
301 Moved Permanently
A 301 Redirect is a permanent redirect which passes ranking power to the redirected page. 301 refers to the HTTP status code for this type of redirect. In most instances, the 301 redirect is the best method for implementing redirects on a website.
302 Found (HTTP 1.1) / Moved Temporarily (HTTP 1.0)
A 302 Redirect is a temporary redirect and passes 0% ranking power and in most cases should not be used.
++307 Moved Temporarily (HTTP 1.1 Only)
A 307 Redirect is the HTTP 1.1 successor of the 302 redirect. While the major crawlers will treat it like a 302 in some cases, it is best to use a 301 for almost all cases.
Meta refreshes are a type of redirect that is executed on the page level rather than the server level. They are usually slower and not a recommended SEO technique. They are most commonly associated with a 5 second count down with text "If you are not redirected in 5 seconds, click here". Meta refreshes do pass some link juice but are not recommended as an SEO tactic due to usability and the loss of link juice passed.