a. The process or condition of sticking or staying attached: the adhesion of the glue to wood.
b. Physics The physical attraction or joining of two substances, especially the macroscopically observable attraction of dissimilar substances.
a. A condition in which bodily tissues that are normally separate grow together.
b. A fibrous band of scar tissue that binds together normally separate anatomical structures.
3. Attachment or devotion, as to a religion or belief.
[French adhésion, from Latin adhaesiō, adhaesiōn-, from adhaesus, past participle of adhaerēre, to adhere; see ADHERE.]
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.