What's the difference between something that it is “connected” and “interconnected?”

I always thought that inter means that the elements I'm talking about has a relation with another one. The word "connected" already has this meaning. So when I read "interconnected" I think about: "something attach-idly joined to another"

I would appreciate if someone can explain this to me.

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The only useful distinction I can make is that connection refers to the linkage between two things (nodes) while interconnection refers to multiple connections among multiple nodes. This is not borne out by examining dictionary definitions, however, and if dictionaries (i.e. current usage) have it right the two are pretty much interchangeable.

If you look at the word roots, interconnection seems pleonastic: con (together) + nectere (bind) already means bind together in connect. Adding inter (between, among) to "bind together" only adds "between" or "among" to the meaning. One wonders how things can be bound together without being "bound together between" — but that is language for you.

Etymonline tells us that interconnect is by far the more recent coinage, first attested in 1865, some three centuries after connect. So I really don't have any good advice other than to mention how I think of the difference, as I did in the first paragraph of this answer.

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I agree with your feeling that interconnection requires multiple connections, I'm rather surprised that you are finding dictionaries not bearing that out. – Uticensis Apr 25 '11 at 11:55

The distinction I draw (and I don't have a source for this unfortunately) between connected and interconnected, is that connected implies a local topological property whereas interconnected implies a more global and mutual topological property.

One example of nodes that are interconnected but not connected:

``````A == B == C
|
|
D
``````

B is connected to A, C, and D. A is connected to B. But A, B, C, and D are all interconnected.

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