Are the two words interchangeable? If so, why is one more common in the singular (interdependence) and the other in the plural (interdependencies)?
# interdependence > # interdependency
# interdependencies > # interdependences
Look at the Google search hit numbers below:
[Edit: Updated the numbers 10-10-18. Note that Google just estimates — based on what it finds in the first moments of its search — the probable number of search results for a given term. But the crude approximation is good enough for this purpose.]
interdependence: 21,200,000
interdependences: 160,000
interdependency: 12,100,000
interdependencies: 3,920,000
Best Answer
Whereas, elementary/primary school teachers would propagate to little children as countable/non-countable nouns, I wish to advise that engineering would prefer the more mathematical terms of
There are four possibilities
XXX-ence and XXX-ency are used interchangeably, with one usage being more prominent than the other.
e.g., Existence vs existency.
XXX-ence is used both qualitatively and quantitatively, where XXX-ency is not valid.
e.g., reference where there is "no such thing as" referency.
XXX-ence is qualitative.
XXX-ency is quantitative.
e.g., dependence vs dependency
XXX-ence is qualitative.
XXX-ency is quantitative.
but XXX-ency is often used in place of XXX-ence.
e.g., dependence vs dependency
In engineering, we would normally say,
Since the words interdependence(y) are derived from dependence(y), then
e.g.,
In engineering, we would use dependencies in place of dependence. Because the quantitative idea would logically imply the qualitative idea. But not the converse, as we would never say,
because it sounds tacky, perhaps.