euchologion vs psalter

euchologion

noun
  • A book of prayers or religious ritual. 

psalter

noun
  • Synonym of Book of Common Prayer, which prominently includes the Psalms. 

  • Synonym of Psalms, particularly when printed as a separate work from the Bible. 

  • Synonym of breviary, which arranges the Psalms for devotional recitation. 

  • A rosary with 150 beads, used for reciting the Psalms in Catholic editions of the Bible. 

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