a. Undisturbed by tumult or disorder; calm or quiet: led a placid life.
b. Not agitated physically; not disturbed: a placid stream.
2. Not easily upset or excited; mild or complacent: a placid demeanor. See Synonyms at calm.
[Latin placidus, from placēre, to please; see plāk-1 in the Appendix of Indo-European roots.]
pla·cidi·ty (plə-sĭdĭ-tē), placid·ness (plăsĭd-nĭs) n.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.