chiefly vs materially

chiefly

adv
  • Especially or primarily; above all. 

  • Mainly or principally; almost entirely. 

adj
  • of or relating to a chief 

materially

adv
  • To a significant degree. 

  • In a material manner; with regard to physical things or characteristics. 

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