nurture vs sustainment

nurture

noun
  • The act of nourishing or nursing; tender care 

  • That which nourishes; food; diet. 

  • The environmental influences that contribute to the development of an individual (as opposed to "nature"). 

verb
  • To nourish or nurse. 

  • To encourage, especially the growth or development of something. 

sustainment

noun
  • The act of sustaining something. 

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