The action of finding an IP address given a HostName, using DNS.
bash-2.05b$ host wlug.org.nz
wlug.org.nz has address 184.108.40.206
wlug.org.nz mail is handled (pri=10) by smtp.wlug.org.nz
A ForwardLookup tends to use A records in DNS, though may also use any combination of CNAME/MX depending on what you're looking for.
Does a ForwardLookup also include things like TXT, SRV and so on? -- NathanWard