Redirect
A rule sending an old URL to a new one. Its absence during a site move is the most expensive technical mistake you can make.
Why it matters when you read an offer
If you are moving a site and this word is absent from the offer, stop the conversation and ask. Its absence is the most expensive mistake described anywhere on this site.
What it looks like in an offer
Migration with no traffic loss is a promise about redirects. Ask in writing for every old address to point to its new equivalent, with a list.