You might call them url shortcodes, shortcuts, abbreviations or otherwise. Firefox calls them keywords. Bookmark a page, edit the bookmark, add a keyword. Now type that keyword into the address bar and hit enter. Boom, it takes you to the bookmarked page.
So instead of typing http://www.scroogle.org/cgi-bin/scraper.htm I can instead just type “search” and boom, I’m there! Props to cryton on freenode#firefox for the info. 
It’s even better than that. If you right click in the scroogle text search box, you can “Add a keyword for this search”. Then you just type ” any-text-here” in your address bar.
Nice, thanks Morgan.
It’s even better than that!
If you put %s in the bookmark URL, then you can add text after your keyword, and it will be included.
For example, add a bookmark for this URL:
http://en.wikipedia.org/w/wiki.phtml?search=%s&go=Go
Set the keyword as ‘wiki’.
Now, go to your address bar, and type: “wiki dyatlov pass accident” and see what happens
It’s getting better with every comment, what will be next I wonder?
It’s even better than that!
There’s a small box, that looks a little like the URL box, that you can just type a word into and it will search for that word! You don’t even have to type in the keyword for the search engine you want to use!
Seriously tho - pretty neat feature…thanks.