bobsled vs troika

bobsled

verb
  • To ride a bobsled. 

noun
  • A short sled, mostly used as one of a pair connected by a reach or coupling; the compound sled so formed. 

  • A sled used to go down a bob track. 

  • The sport of travelling down a bob track as fast as possible. 

troika

noun
  • A Russian carriage drawn by a team of three horses abreast. 

  • A party or group of three, especially a ruling council of three people in Russian contexts. 

How often have the words bobsled and troika occurred in a corpus of books? (source: Google Ngram Viewer )