Unix command "host" - is there Windows equivalent?

This question is more suited to Super User, but the command you're looking for is nslookup. Both are (at their most basic) used to look up IP addresses for hostnames. You can run cmd and do nslookup hostname the same way you'd do host hostname. If you need something other than the IP address, the command-line arguments will differ. Run nslookup with no arguments and type help at the prompt for details.

Although you will be able to find the DNS resolution using nslooukup, there is no direct equivalent to the host command in Windows. There is a similar question on Super User.