Sentence:  I've seen one monkey force open the jaws of his brother, resolutely introduce his fingers, pluck from the sanctuary of his cheek the <WSD>filbert</WSD> he had just stowed there for his private nutrition and delight, and crunch and eat it with a stern ecstasy of selfishness, himself ... 
Meaning of the word marked with <WSD> tags:  The hazelnut.