Origin Story
The word lunatic holds an old belief about the moon. The Latin word for moon is luna, and people once believed that the waxing and waning of the moon swayed the human mind as well. Under a full moon especially, they thought the mind grew unsettled and fits worsened. So the Latin lunaticus, "moon-struck," was born, and it became the English lunatic. The idea that the moon drives people mad has no medical basis, yet the belief remains intact within the word.
The same luna ("moon") gives us lunar ("of the moon," as in lunar module), and the English idiom "once in a blue moon" ("very rarely") is tied to the moon as well. For a long time the moon was thought to govern both the human mind and human fate.
-
Online Etymology Dictionarylunatic (adj.): late 13c., "affected with periodic insanity," from Old French lunatique, from Late Latin lunaticus "moon-struck," from Latin luna "moon"
-
Merriam-Webster Dictionarylunatic: from Late Latin lunaticus, from Latin luna moon; from the belief that lunacy fluctuated with the phases of the moon
-
Oxford English Dictionarylunatic: from Latin lunaticus, from luna "moon," reflecting the belief that the moon caused intermittent insanity
Word Evolution
Words from the Same Root
Memory Hook
Remember that the luna in lunatic is Latin for "moon." It comes from the old belief that the moon stirs the mind.
""People once blamed even the troubles of the mind on the distant moon.""
