Kingdom
Part of speech: noun
Definition: A nation having as supreme ruler a king and/or queen. A rank in the classification of organisms, below domain and above phylum; a taxon at that rank (e.g. the plant kingdom, the animal kingdom)
Realm
Part of speech: noun
Definition: An abstract sphere of influence, real or imagined.The domain of a certain abstraction.A territory or state, as ruled by a specific power, and particularly those territories ruled by a king.
Example sentence: Modern secular thought has its own dualism: It treats only the physical world as knowable and testable, while locking everything else - mind, spirit, morality, meaning - into the realm of private, subjective feelings. The so-called fact/value split.