decade vs decennium

decade

noun
  • A period of ten years , particularly such a period beginning with a year ending in 0 and ending with a year ending in 9. 

  • Any of the sets of ten sequential braille characters with predictable patterns. 

  • A group, set, or series of ten 

  • A period of ten days, (history) particularly those in the ancient Egyptian, Coptic, and French Revolutionary calendars. 

  • A series of prayers counted on a rosary, typically consisting of an Our Father, followed by ten Hail Marys, and concluding with a Glory Be and sometimes the Fatima Prayer. 

  • A set of resistors, capacitors, etc. connected so as to provide even increments between one and ten times a base electrical resistance. 

  • The interval between any two quantities having a ratio of 10 to 1. 

  • A set of ten electronic devices used to represent digits. 

decennium

noun
  • Synonym of decade: a ten year period. 

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