Hi LeM12, It sounds like that particular site does not save any set font settings, Firefox does not remember individual settings for specific sites. You can, however do it with this add on Custom Page Zoom.

The current option in Firefox is to set the font and page color for all sites or for no sites: Change the fonts and colors websites use

You seem not to understand the actual problem. I do not care if sites remember the zoom level or not. In fact they do remember the zoom level if I zoom out the entire page, and that's not the problem. But it cannot zoom out fonts! Just try it yourself. Go to "Option > Content > Fonts&Colors > Advanced" and set the "Minimum font size" to 22. Then in the "View" menu set "Zoom text only" option. Go then to any webpage and try to zoom out below those 22 (I suggest you visualdictionaryonline.com, where you'll understand why I'm so frustrated; and it's not the only one such site). You won't be able! It's just stuck to those 22 and resists to be smaller. The only option is to go again to "Option > etc" and set the "Minimum font size" to "None" or at least to a lesser value (say, 12). But I want my 22 by default for every site, it is just a handful of sites cannot use such a big font without messing up the webpage design. But I do not want to go to the "Options" every time. It is the problem with the browser which zooming cannot override the set minimum font size. Just why? Why can't it do such a trivial thing?

P.S. I've tried the suggested plugin. Just a waste of time. And I for sure know very well where the basic settings are, I've been using FF from its very first version. So no need to provide links to such trivial help pages for noobs. Probably there could be some little known option in about:config, this is why I'm asking.