"[fall into|drop into|land into] {one's} lap"의 정의 및 의미

What is the origin of the idiom "fall into someone's lap" and when to use it?

The idiom "fall into someone's lap" is used to refer to a situation where something unexpected or fortunate happens to someone without much effort on their part. The origin of this idiom can be traced to the idea of a valuable or desirable object literally falling into someone's lap, as if it were a gift from the heavens. It is often used to describe unexpected opportunities, windfalls, or favorable circumstances.