means A person responsible for guarding, supervising, or enforcing rules in a particular place — like a prison, a college, or a stretch of countryside.

from From Old North French 'wardein,' a cousin of the standard French 'gardein' (modern 'gardien,' guardian) — both trace back to a Germanic root meaning 'to watch, guard,' the same source that gives English 'ward' and 'guard.' English greedily borrowed both forms, so 'warden' and 'guardian' are essentially the same word arriving by two doors, with the harder Norman 'w' marking the older entry.