Sentence:  Over the weekend, an impressive crossword-solving computer program, called Dr. Fill, which I wrote about earlier, matched its digital wits against the <WSD>wetware</WSD> of 600 of the nation's best human solvers at the American Crossword Puzzle Tournament in Brooklyn. 
Meaning of the word marked with <WSD> tags:  The human brain or mind, often specifically as a computing element. Adapted as a biological parallel to hardware and software. Common in the cyberspace genre of science fiction.