orchestra vs sinfonietta

orchestra

noun
  • A large group of musicians who play together on various instruments, usually including some from strings, woodwind, brass and/or percussion; the instruments played by such a group. 

  • A semicircular space in front of the stage used by the chorus in Ancient Greek and Hellenistic theatres. 

  • The area in a theatre or concert hall where the musicians sit, immediately in front of and below the stage, sometimes (also) used by other performers. 

sinfonietta

noun
  • A small orchestra. 

  • A small-scale symphony (either in length or size of orchestra needed). 

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