Simon Le Fort wrote:In that case, each of the heads could be considered the singular components. The words BICEPS clearly has plurality or at least duality at its core.
The word "duality" also has duality as its core, that doesn't tell you anything about its grammatical function. I'm confused about your point. Before you were saying that BICEP is the name of the muscle, now you're saying that BICEP should be allowed as "one end of the biceps". The latter use might well be grammatical, if it exists at all, but probably far too obscure for a dictionary of only 2000 pages.
Simon Le Fort wrote:Disallowing BICEP is as out of touch with reality, as would be disallowing BUS in favour of OMNIBUS.
You keep saying that, but you haven't produced any evidence. The ODE is a corpus-based dictionary based on statistical analysis of several orders of magnitude more text than any of us have seen in our entire lives, so I would be cautious about claiming to know better. I trawled through several pages of
Google results for BICEP and all of them were from dodgy body-building websites.
Simon Le Fort wrote:Ongoing defence of OED infallibity bears all the tunnel vision of a cyclop.
You haven't read many of my posts then

The ODE is full of strange inconsistencies and contradictions, and I've criticised it many times before. That doesn't mean they're wrong in this case.