Emily Dickinson Lexicon

GLOOM, n. [Scot. gloum, gloom, a frown. In D. lommer a shade, and loom is slow, heavy, dull. In Sax. glomung is twilight.]

1. Obscurity; partial or total darkness; thick shade; as, the gloom of a forest, or the gloom of midnight.
2. Cloudiness or heaviness of mind; melancholy; aspect of sorrow. We say, the mind is sunk into gloom; a gloom overspreads the mind.
3. Darkness of prospect or aspect.
4. Sullenness.