The original usage of “equanimity” in the early 17th century expressed fairness in judgment. A good judge could be said to rule with equanimity. However, that meaning has dropped out of usage, and the modern meaning of “equanimity” refers to someone’s state of mind or behavior being well balanced. The word comes from the Latin “aequanimitas,” with “aequus” meaning “equal” and “animus” meaning “mind, soul.” It was developed in relation to the Latin phrase “aequo animo ferre,” meaning “to bear with equal mind.”