I know what the word means, but I’m unsure how to use it in a sentence. In my native language, Danish,“backorder” translates to “Restordre” and when something is unavailable, we say it’s"i Restordre",which translates directly into English as “in backorder”, but I’m not sure that’s correct English. Do English people say that or just “backordered” or something else?
Or in pain, in understanding, in accordance with, in support of, in disbelief, etc.
English in a nutshell. Here is a rule. It always works except in this 300 million examples when not. I hate it.
Just remember each individual word and phrase in the English language, easy peasy!
I’d argue that “on” is used more when something physical and specific is happening rather than a concept happening