External Host, DH Registration, How To Point Them?

I know this must be a super basic question, but I am not familiar with the lingo to search for it. I have a hosted website at another host. I have a domain name registered at DH. I want my domain name regiestered at DH to point to the hosted site at another host. Question number 1 is, how do I say that using the correct terms? Question number 2 is, how do you do it? Thanks!

Do I need to make an “A record” at DreamHost? What is that? How do you do it?

An A record is when you are hosting the domain of the same name elsewhere. You most likely are looking for a 301 redirect. see http://wiki.dreamhost.com/Redirect_Domain