This is when you type "the" and suddenly "the thing I was looking for yesterday" shows up in the address bar so that when you hit Enter it searches for the thing you searched for yesterday not the thing you want today.
I can't find the option to disable this. Disabling Settings > Advanced > Privacy > "Use a prediction service to help complete searches and URLs typed in the address bar" doesn't disable it. That's for something different.
I've looked through the questions/answers here and Google's bug reports (which they've conveniently disabled comments for), and not seen the one comment that maybe Google hasn't considered (or other users haven't mentioned):
This feature is the primary reason I use Incognito for many searches (making Google's search engine less useful to their bottom line and my surfing habits and their ad targeting); because my one-offs or two-offs I needed at the moment don't auto-populate in the search bar causing me to hit Enter on an unintended search or have to hit Backspace to delete the useless text.
I can't comment on any of the questions/answers/comments here (reputation not anywhere near high enough) so I'm leaving this one tidbit to see if anyone else is in my same scenario or has since discovered a tweak to disable this annoying and counter-productive (even to Google and its developers) feature.