mañana vs once

mañana

adv
  • Some unspecified time in the future. 

  • Tomorrow. 

once

adv
  • Formerly; during some period in the past. 

  • Multiplied by one: indicating that a number is multiplied by one. 

  • One and only one time. 

conj
  • As soon as; when; after. 

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