hark back vs invert

hark back

verb
  • To return to where one has previously been; to retrace one's steps. 

  • To allude, return, or revert (to a subject previously mentioned, etc.); also, to evoke, or long or pine for (a past era or event). 

  • To call back (hounds); to recall. 

  • Of hounds: to retrace a course in order to pick up the lost scent of prey. 

noun
  • An act of hounds retracing a course in order to pick up the lost scent of prey. 

  • An act of alluding, returning, or reverting (to a subject previously mentioned, etc.); also, an act of evoking, or longing or pining for (a past era or event). 

invert

verb
  • To turn (the foot) inwards. 

  • To divert; to convert to a wrong use. 

  • To turn (something) upside down or inside out; to place in a contrary order or direction. 

  • To move (the root note of a chord) up or down an octave, resulting in a change in pitch. 

  • To undergo inversion, as sugar. 

noun
  • The base of a tunnel on which the road or railway may be laid and used when construction is through unstable ground. It may be flat or form a continuous curve with the tunnel arch. 

  • A skateboarding trick where the skater grabs the board and plants a hand on the coping so as to balance upside-down on the lip of a ramp. 

  • An invertebrate. 

  • An inverted arch (as in a sewer). 

  • An elevation of a pipe at a certain point along the pipe. 

  • The lowest point inside a pipe at a certain point. 

adj
  • Subjected to the process of inversion; inverted; converted. 

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