She is in order (3)
I believe the answer is:
nun
This could be a double definition.
'she' is the first definition.
Both the answer and definition are singular nouns.
Perhaps you can see a link between them that I can't see?
'order' is the second definition.
The definition and answer can be both related to communication as well as being singular nouns.
Maybe there's a link between them I don't understand?
'is in' is the link.
Can you help me to learn more?
(Other definitions for nun that I've seen before include "Religious sister" , "Woman in religious order" , "Priory female" , "Convent dweller" , "Holy sister" .)