task vs undertaking

task

noun
  • A process or execution of a program. 

  • Any piece of work done. 

  • A difficult or tedious undertaking. 

  • An objective. 

  • A piece of work done as part of one’s duties. 

verb
  • To charge, as with a fault. 

  • To assign a task to, or impose a task on. 

  • To oppress with severe or excessive burdens; to tax 

undertaking

noun
  • That which is undertaken; any business, work, or project which a person engages in, or attempts to perform; an enterprise. 

  • A promise or pledge; a guarantee. 

  • The business of an undertaker, or the management of funerals. 

  • The act of one who undertakes (in either sense). 

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