court of first instance vs tribunal

court of first instance

noun
  • a court of law where legal proceedings are first heard. 

tribunal

noun
  • An assembly including one or more judges to conduct judicial business; a court of law. 

  • A kind of village hall used to transact business, to quarter troops and travellers, and to confine prisoners. 

How often have the words court of first instance and tribunal occurred in a corpus of books? (source: Google Ngram Viewer )