fine structure

American  

[fahyn] / faɪn /

noun

Physics.

1. a group of lines that are observed in the spectra of certain elements, as hydrogen, and that are caused by various couplings of the azimuthal quantum number and the angular momentum quantum number.

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fine structure British  

noun

1. the splitting of a spectral line into two or more closely spaced components as a result of interaction between the spin and orbital angular momenta of the atomic electrons Compare hyperfine structure

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Etymology

Origin of fine structure

First recorded in 1915–20

Example Sentences

Until recently, scientists struggled to observe the fine structure of this process in detail.

From Science Daily • Apr. 30, 2026

Despite this coverage of sensors measuring the magnetic field, "diagnosing the detailed fine structure is a nightmare," Mann said, since the magnetic effects from smaller scale structures can magnetically cancel on the ground.

From Salon • Apr. 16, 2025

The method, she says, can preserve “the fine structure of very, very small parts of cells” better than the chemical fixatives normally used in microscopy.

From Science Magazine • Dec. 2, 2024

The envelope is made up of slow fluctuations in the amplitude of the waveform, whereas the fine structure consists of the rapid fluctuations in frequency and amplitude within the waveform.

From Scientific American • May 4, 2022

I felt the warmth of blood rush to your cheek, the fine structure of your jaw, like a bird's light bones.

From "What the Night Sings" by Vesper Stamper