The way I removed countless searches I hadn't known were in history was to use History > Clear Recent History (ctl+shft+del) > Time range to clear : everything > Form & Search history.

Thanks for your response, Terry. As indicated in my question I did exactly what you have suggested and have done this for years not realizing until recently that the search bar subjects were not being removed. I have deleted a ton of them one by one and expect to do this well into the future.

These are search history entries on the classic Search Bar with the little clock icon next to them?

Or in the address bar drop-down?

Thanks for taking the time to frame your response. I use Yahoo rather than Google. However, good news is that I've removed all the past bar searches. From now on this will be a daily task.