- Henry Gwyn Jeffreys [gwin] /gwɪn/, 1887–1915, English physicist: pioneer in x-ray spectroscopy.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- Henry Gwyn-Jeffreys. 1887–1915, English physicist. He showed that the wavelengths of X-rays emitted from the elements are related to their atomic numbers