The word "placid" is frequently used to evoke a serene, undisturbed calmness in both character and scene. Authors employ it to describe subtle, steady qualities—a placid smile or expression that hints at inner composure and quiet dignity ([1], [2], [3], [4])—while others use it to paint landscapes and states of being imbued with tranquility, such as the calm, mirror-like surface of a lake or the placid bosom of a river ([5], [6]). In narratives, a placid demeanor often contrasts with moments of inner turmoil or external action, highlighting a character’s steady nature even when circumstances grow tense ([7], [8]). Moreover, in poetic and classical contexts the term underscores an ideal of peaceful permanence, whether describing the placid soul of a heroic figure or the calm expanses of nature ([9], [10]).