What It Is
A nameserver is a computer that stores your domain’s DNS records and answers lookups for them. Your registrar keeps a note saying which nameservers are in charge of your domain, usually two or more for backup. Picture a receptionist who knows which office everyone sits in. Anyone asking for your domain is sent to that receptionist for directions.
Why It Matters for Your Business
Changing nameservers moves control of all your DNS records to a new provider at once. That is a big switch. If a business points its nameservers to a new web host but forgets to recreate its email records there, email can stop arriving. Knowing where your nameservers point tells you where to make DNS changes.
Good to Know
If your DNS edits seem to have no effect, check your nameservers first. You may be editing records at a company that is not actually in charge of your domain. A WHOIS lookup or your registrar’s dashboard will show which nameservers your domain is using right now, so start there before changing anything.