lower chamber vs senate

lower chamber

noun
  • The lower legislative chamber in a bicameral legislature; in many cases, the one that is directly elected and/or has more practical power, such as the power to raise and spend money. 

senate

noun
  • In some bicameral legislative systems, the upper house or chamber. 

  • A group of experienced, respected, wise individuals serving as decision makers or advisors in a political system or in institutional governance, as in a university, and traditionally of advanced age and male. 

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