1. An infectious disease characterized by cycles of chills, fever, and sweating, caused by a protozoan of the genus Plasmodium in red blood cells, which is transmitted to humans by the bite of an infected female anopheles mosquito.
2. Archaic Bad or foul air; miasma.
[Italian, from mala aria, bad air (from the belief that malaria was caused by vapors emanating from swamps, rather than mosquitos that bred there ) : mala, feminine of malo, bad (from Latin malus; see mel-3 in the Appendix of Indo-European roots) + aria, air; see ARIA.]
ma·lari·al, ma·lari·an, ma·lari·ous adj.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 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.