Changing one word to another:

Change it when displayed on your blog, or change it permanently?

change how it’s displayed on your blog.

Example:

You have a bunch of entries with the word “apple” in it

You want to change every entry that has the word “apple” and change it to “oranges”

There’s a number of plugins out there that do this in different ways. You’ll find some listed here:

https://codex.www.ads-software.com/Plugins/Posts_Formatting

My W-P is an example:

https://guff.szub.net/w-p/

EDIT: Actually, looking that the Codex Plugins page above, I’m only really seeing mine listed. But there *are* others out there. Really. :/

Thank you so much Kafkaesqui! ??

Yeah, there is one that does this. Coffee2code released it.
https://www.coffee2code.com/archives/2004/06/29/plugin-text-replace/
Good luck!