It is the hypothetical source of/evidence for its existence is provided by: Sanskrit trapate "is ashamed, confused," properly "turns away in shame;" Greek trepein "to turn," tropos "a turn, direction, course," trope "a turning;" Latin trepit "he turns."
1847, back-formation from allotropy "variation of physical properties without change of substance," from Greek allotropos "in another manner;" see allo- "different" + -trope "way, manner." Diamond is an allotrope of carbon. Related: Allotropic.
<a href="https://www.etymonline.com/word/-trope">Etymology of -trope by etymonline</a>
Harper, D. (n.d.). Etymology of -trope. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/-trope