pre·ven·tive (prĭ-vĕntĭv) also pre·ven·ta·tive (-tə-tĭv)
1. Intended or used to prevent or hinder; acting as an obstacle: preventive measures.
2. Carried out to deter expected aggression by hostile forces.
3. Preventing or slowing the course of an illness or disease; prophylactic: preventive medicine; preventive health care.
1. Something that prevents; an obstacle.
2. Something that prevents or slows the course of an illness or disease.
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.