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.]
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