Sentence:  A great writer of the last epoch, comparing Russia to a swift <WSD>troika</WSD> galloping to an unknown goal, exclaims 'Oh, <WSD>troika</WSD>, birdlike <WSD>troika</WSD>, who invented thee!' and adds, in proud ecstasy, that all the peoples of the world stand aside respectfully to make way for the recklessly galloping <WSD>troika</WSD> to pass. 
Meaning of the word marked with <WSD> tags:  A Russian carriage drawn by a team of three horses abreast.