from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Free from commotion or disturbance. See Synonyms at calm.
- adj. Free from anxiety, tension, or restlessness; composed.
- adj. Steady; even: a tranquil flame.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Free from emotional or mental disturbance.
- adj. Calm; without motion or sound.
from the GNU version of the Collaborative International Dictionary of English
- adj. Quiet; calm; undisturbed; peaceful; not agitated.
from The Century Dictionary and Cyclopedia
- Quiet; calm; undisturbed; not agitated; serene.
- Synonyms Placid, Serene, etc. See calm.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. (of a body of water) free from disturbance by heavy waves
- adj. not agitated; without losing self-possession
Middle English tranquill, from Latin tranquillus; see kweiə- in Indo-European roots.(American Heritage® Dictionary of the English Language, Fourth Edition)
From Latin tranquillus. (Wiktionary)