Once upon a time, a bird sang a sweet song.

Meaning: This phrase is commonly used to introduce a fairy tale or a story set in an unspecified time period.

Choice of Words: Upon is a preposition that means on or in a position touching or resting on something. Time refers to a period or point in history. When you combine them, "Upon a time" creates a sense of a distant or unspecified past, often used in storytelling.

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Related Expressions