Phrases & IdiomsIdiom guide

A Fine Line

A “fine line” is a very small distinction between two things, often used when crossing that distinction changes what is acceptable or appropriate.

Quick answer

A “fine line” means a very small or delicate difference between two things.

Key details

Canonical Forma fine line
Core Meaninga very small difference between two things, often where one side is acceptable and the other is not

Further guidance

History Boundary

Current dictionary-supported meaning is published without claiming an exact inventor, coinage date, or absolute first use.

Meaning

a very small difference between two things, often where one side is acceptable and the other is not

Usage Boundary

The expression highlights a narrow distinction or balance; it does not mean the two things are literally identical.

Sources and evidence

Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.

  1. A fine line — Cambridge Dictionary (opens in a new tab)Cambridge Dictionary · Current idiomatic meaning of a fine line

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