Coupler or coupling? Which one is correct?

So what is it... a "coupling" or "coupler"? This is an age old question that, inside the industrial sector, could quite possibly be as fierce as the "soda vs pop" debate that continues to rage through the United States. While corporate budgets have not afforded us the opportunity to map out the United States or take formal studies... Lovejoy is decidedly a "coupling" company, as are all of the handful of other major coupling competitors that our team has surveyed.

Wikipedia also appears to be on the side of "coupling", which defines a coupling as "a device used to connect two shafts together at their ends for the purpose of transmitting power".

But what does Wikipedia say when you search for coupler... it defines it as "is a word used to describe any of a number of things"... one of which is "a connector between two moving parts to relay the motion, such as a universal joint or oldham coupler". It then goes on to say... "see also: Coupling".

Given universal joints and oldham are absolutely coupling types... what does all this mean exactly? Are they interchangeable?

Merriam-Webster dictionary doesn't seem to think so. Among its definitions, a coupling is "a device that connects two parts or things".... but, search coupler and you will find no reference for anything mechanical power transmission related.

So can Merriam-Webster and Wikipedia be at odds? Not really. Upon closer inspection, the oldham coupler reference on Wikipedia actually points back to the Wikipedia coupling page... and the universal joint reference points to a universal joint page that calls a universal joint a coupling (not coupler).

As such, it is our current opinion that "coupling" is the true and proper term... but that doesn't mean that the "coupler" folks aren't without their merits. We just completed another post on the word "coupling", and it turns out it is a very unusual word type (being that it is verb that also can/does behave as a noun).
 
Do you agree or disagree with our analysis? We are certainly still open to revisit the subject/revise our position... so please let us know in the comment field below.

And, in the meantime... should it be any consolation for "coupler" fans, Lovejoy promises to continue thinking no less of your use of the term, and will still be happy to take care of your every "coupler" need. We just ask for your forgiveness in advance if/when our packing slip, website, and everything else we cite incorrectly calls your favorite Lovejoy "coupler" a "coupling".