Sentence:  And it was while all were passionately intent upon the pleasing and snake-like progress of their <WSD>uncle</WSD> that a young girl in furs, ascending the stairs two at a time, peeped perfunctorily into the nursery as she passed the hallway&mdash;and halted amazed. 
Meaning of the word marked with <WSD> tags:  The brother or brother-in-law of one's parent.