More so vs. moreso — which form is correct?

Sometimes even native speakers are confused when it comes to certain words or phrases, no matter what language is concerned. When you think about two variants, more so and moreso, you most likely assume that only the first version is correct. Well, appearances can be deceptive.

More so or moreso — which is the incorrect form?

Every dictionary or autocorrect you consult will tell you that more so is the only correct spelling of the phrase. Yet, when reading some contemporary documents, especially the American ones, you may also encounter the expression moreso. This form, though disapproved by linguists, has been gaining popularity.

Moreso vs. more so in publications

Even though moreso is not yet officially approved, you can already come across it in some literary works.

‘Being able to talk to ravens is a sensible magic. Moreso than most of the fool stuff you see flying about’.

T. Kingfisher, The Raven and the Reindeer, 2016

It is still easier to find moreso in other sources, even in official documents:

From the journal Chemistry Education Research and Practice:

‘Moreso, at-risk students found to have performed well on mole concept and stoichiometry went on to perform similarly as their not at-risk peers’.

United Nations Meetings Coverage and Press Release:

‘Moreso, it updated its penal code to include provisions that prevent and punish crimes against humanity, as well as genocide, torture and war crimes in general’. Finally, let’s have a look at the good, old more so in literature:

‘When I was alive, I believed — as you do — that time was at least as real and solid as myself, and probably more so’.

Peter S. Beagle, The Last Unicorn, 1968

‘Stupid is just as destructive as Evil, maybe more so, and it’s a hell of a lot more common’.

Jim Butcher, Vignette, 2008