E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Monitor.
So the Romans called the nursery teacher. The Military Monitor was an officer to tell young soldiers of the faults committed against the service. The House Monitor was a slave to call the family of a morning, etc.
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Monitor. An ironclad with a flat deck, sharp stern, and one or more movable turrets.
