1. The act or process of joining or the condition of being joined.
2. A place where two things join or meet, especially a place where two roads or railway routes come together and one terminates.
3. A transition layer or boundary between two different materials or between physically different regions in a single material, especially:
a. A connection between conductors or sections of a transmission line.
b. The interface between two different semiconductor regions in a semiconductor device.
c. A mechanical or alloyed contact between different metals or other materials, as in a thermocouple.
[Latin iūnctiō, iūnctiōn-, from iūnctus, past participle of iungere, to join; see yeug- in the Appendix of Indo-European roots.]
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.