We had to refactor all our internal and external documentation from Master -> leader and slave -> subordinate. So you get things like “… in subordinate mode”.
Thankfully the actual code remained the same (because only engineers look at it).
I've seen "slave nodes" renamed to "children nodes". Because a node that exists solely to support another, more important node, has to carry out the orders it receives from that node, must not do anything on its own, and will be terminated and wiped if it diverges from the vision the main node has — yes, it's a child node alright. You see, that's how children are generally treated in our enlightened society, so the new name is now properly evocative, and has no unfortunate implications.