Since Firefox version 78, the Firefox address bar remembers the last two search terms entered by default. Corresponding results are marked by a clock symbol in front of them. If you would like to change this, you can do this with a change in about:config.
Change search suggestions address bar
This is what it looks like by default with the two notes, recognizable by the clock symbol in front of them.

If you want to change this note, you can do so with a change in about:config.
about:config explanation
First, start Firefox and then type in the address bar at the top
about:config
and then presses the Enter key and confirms the warning message by clicking on the "I am aware of the dangers!" button.

Then make the following entry in the top left under Search:
browser.urlbar.maxHistoricalSearchSuggestions
On the right side, under Value, the standard entry is 2.

Change search suggestions address bar
Now double-click this value with the left mouse button and either change it to 0, in which case no result is displayed at all, or increase the value as you wish.
As a test, I increased the value to 3.
Then click on the right blue arrow and confirm the change.
Then simply close the about:config page again.
The change is applied immediately by Firefox.
From now on, 3 entries will be displayed, as can be seen from the clock symbol in front of them.

If you want to change that again, simply click on the back arrow in about: config on the far right in the column with the entry and set the value back to standard 2.