promise vs spell

promise

verb
  • To give grounds for expectation, especially of something good. 

  • To commit to (some action or outcome), or to assure (a person) of such commitment; to make an oath or vow. 

noun
  • A transaction between two persons whereby the first person undertakes in the future to render some service or gift to the second person or devotes something valuable now and here to his use. 

  • A placeholder object representing the eventual result of an asynchronous operation. 

  • Reason to expect improvement or success; potential. 

  • an oath or affirmation; a vow 

spell

verb
  • To indicate that (some event) will occur. 

  • To be able to write or say the letters that form words. 

  • To work in place of (someone). 

  • To constitute; to measure. 

  • To rest (someone or something), to give someone or something a rest or break. 

  • To clarify; to explain in detail. 

  • Of letters: to compose (a word). 

  • To rest from work for a time. 

  • To put under the influence of a spell; to affect by a spell; to bewitch; to fascinate; to charm. 

  • To write or say the letters that form a word or part of a word. 

noun
  • An uninterrupted series of alternate overs bowled by a single bowler. 

  • A magical effect or influence induced by an incantation or formula. 

  • An indefinite period of time (usually with a qualifier); by extension, a relatively short distance. 

  • Words or a formula supposed to have magical powers. 

  • A definite period (of work or other activity). 

  • A splinter, usually of wood; a spelk. 

  • The wooden bat in the game of trap ball, or knurr and spell. 

  • A period of rest; time off. 

  • A period of illness, or sudden interval of bad spirits, disease etc. 

  • A shift (of work); (rare) a set of workers responsible for a specific turn of labour. 

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