senate vs upper house

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. 

upper house

noun
  • The upper legislative house in a bicameral legislature; usually smaller and having more restricted power than the lower house. 

  • Coordinate terms: lower house, sole house 

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