Exchange vs. interchange

[Marinka]

English Synonym, Elementary Level

ESL/EFL Test #64 "Synonyms for change", question 10

The two sisters are very close, they ......... letters every week.

(a) alter
(b) shift
(c) exchange
(d) switch

English Synonym, Elementary Level

ESL/EFL Test #64 "Synonyms for change", answer 10

The two sisters are very close, they exchange letters every week.

Correct answer: (c) exchange

Your answer was: correct
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What is the exact difference between "exchange" & " interchange"?

Marinka

[Mister Micawber]

.
I see from the dictionary that the verb interchange can also mean 'give to, and receive from, one another'-- but usually it is used to mean that one item is replaced with another. Two machines, for instance, may have interchangeable parts-- meaning that the widget wheel in one machine can be used also in the other machine.

This concept or connotation does not apply in the exchange of letters, as each letter is unique; in any case, the normal usage is for exchange in the case of correspondence and interchange in the case of identical widget wheels.
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Canadian-American native speaker
who teaches English for a living at Mister Micawber's
ESL cafe: Interview with Mister Micawber