adverbial phrase vs mantra

adverbial phrase

noun
  • A phrase that collectively modifies a verb, adjective, another adverb, or a prepositional phrase. 

mantra

noun
  • A slogan or phrase often repeated. 

  • The hymn portions of the Vedas; any passage of these used as a prayer. 

  • A phrase repeated to assist concentration during meditation. 

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