metrical foot vs rhythm

metrical foot

noun
  • The basic unit of the underlying rhythm of verse 

rhythm

noun
  • The tempo or speed of a beat, song or repetitive event. 

  • A specifically defined pattern of such variation. 

  • A regular quantitative change in a variable (notably natural) process. 

  • Controlled repetition of a phrase, incident or other element as a stylistic figure in literature and other narrative arts; the effect it creates. 

  • The variation of strong and weak elements (such as duration, accent) of sounds, notably in speech or music, over time; a beat or meter. 

  • A flow, repetition or regularity. 

  • The musical instruments which provide rhythm (mainly; not or less melody) in a musical ensemble. 

  • A person's natural feeling for rhythm. 

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