E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Amicus curiæ (Latin, a friend to the court).
One in the court who informs the judge of some error he has detected, or makes some suggestion to assist the court.
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Amicus Plato, sed magis amica Veritas (Plato I love, but I love Truth more) A noble dictum attributed to Aristotle, but certainly a very free translation of a phrase in the Nicomachean Ethics (Where both are friends, it is right to prefer Truth)