I use Google search from my Chrome omnibox quite a bit. One of my favorite searches is “define <term>”.
Somehow my “define” got hijacked so that when I typed it, Chrome switched to a search of word.sc. Fortunately, I knew this probably would be Chrome’s settings for Search Engines (top right wrench or three horizontal lines > Settings > Show advanced link > Manage Search Engines).
Scroll down to the bottom of the search engine list and click the X next to word.sc. This removes it as a search option.
Basically, Chrome collects search engines from the sites I visit. If you enter the keyword for the search engine, then the omnibox searches that site instead of Google. So sneaky.