An A (address) record is a part of the zone file that assigns a hostname (e.g.: support.yourdomain.com) to a specific IP address (e.g.: 123.123.123.123). For example, you can use an "A record" to designate abc.yourdomain.com to send traffic to your web site at IP address 209.15.32.135. You can also designate xyz.yourdomain.com to go to a separate IP address.