Go Search
There are two ways to search Wikipedia, the Go button and Search. After you put your keyword in the searchbox, clicking Go (or Enter on keyboard) will try to take you directly to the page. Except for the first letter, it looks for an exact capitalization match of the keyword you enter. If it can't find a match, it will show a red link, ask if you want to create or request it, and try to return a list of articles that contain the keyword. Clicking Search will always try to return a list of articles; as will red links if a match is not found.
Read more: Wikipedia:Go button, Wikipedia:Searching