second string vs standby

second string

adj
  • Not as good; of a lower quality or condition. 

noun
  • A unit of players which is considered to have a secondary level of talent and which usually plays after the first string. 

standby

verb
  • To wait briefly, as for additional communication by radio or telephone; alternative spelling of stand by 

noun
  • Something that is standard, well-tested, or frequently used. 

  • sleep mode 

  • A state of readiness without immediate involvement; remaining in preparation for (a sudden or unforeseen event or situation). 

  • Waiting at the airport in the hope of getting a seat on a flight that is already booked out. 

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