Sentence:  It was a working document, a sort of lab notebook, and since I have called it a <WSD>daybook</WSD>, it has become the most valuable resource I have It takes me about six weeks to fill a <WSD>daybook</WSD>, and when I'm finished with one I go back through it and pick out anything that I need to work on in the next book. 
Meaning of the word marked with <WSD> tags:  A daily chronicle; a diary.