early vs henceforth

early

adv
  • Soon; in good time; seasonably. 

  • At a time before expected; sooner than usual. 

noun
  • A shift (scheduled work period) that takes place early in the day. 

adj
  • Near the start or beginning. 

  • Near the start of the day. 

  • Having begun to occur; in its early stages. 

  • At a time in advance of the usual or expected event. 

  • Arriving a time before expected; sooner than on time. 

  • Of a star or class of stars, hotter than the sun. 

henceforth

adv
  • From now on; from this time on. 

  • Further within this document. 

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