Originally the word means an arrowslit, a narrow vertical window in a wall to shoot from.
Loopholes are distinct from lacunae, although the two terms are often used interchangeably. In a loophole, a law addressing a certain issue exists, but the law can be legally circumvented due to a technical defect in the said law. A lacuna, on the other hand, is a situation whereby no law exists in the first place to address that particular issue.
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