slightly off-topic: 2 types of search engine?

Please could someone tell me how to distinguish by name the 2 types of search engine
http://www.yahoo.com
http://www.google.com
the one you type a query in, the other you select keywords.
I am in the process of redisigning our homepage.
and choosing definitions for this:
<meta name="keywords" content="
ours is the second type.

jonathan chetwynd
IT teacher (LD)
jc@signbrowser.org.uk