Definition of D line
: a yellow persistent first line of the principal series of the sodium spectrum constituting in the Fraunhofer lines a doublet whose nearly equal components have wavelengths 5895.93 and 5889.96 angstroms respectively
Love words? Need even more definitions?Merriam-Webster unabridged
Words at Play
- Hot Enough for You? Words for the Summer Heat
- Where Does 'Run-of-the-Mill' Come From?
- The Provenance of 'Providence'
- The Good, The Bad, & The Semantically Imprecise - 8/16/19
Ask the Editors
- On Contractions of Multiple Words
- A Look at Uncommon Onomatopoeia
- Is Singular 'They' a Better Choice?
- Summer 2019 Words of the Day Quiz Take the quiz
- Obscure Shapes Take the quiz
- Name That Thing Take the quiz
- Syn City Play the game