Sentence:  It was flood-tide along Fifth Avenue; motor, brougham, and victoria swept by on the glittering current; pretty women glanced out from limousine and <WSD>tonneau</WSD>; young men of his own type, silk-hatted, frock-coated, the crooks of their walking sticks tucked up under their left arms, passed on the Park side. 
Meaning of the word marked with <WSD> tags:  An old-style open passenger vehicle with a '''tonneau''' (rear compartment with seats).