Grammar Nazi Question

[lawgrad91]

Oh, Wilson....(and anyone else who can shed some light on this)

I was reading an article this morning about the murder trial of Casey Anthony, charged with killing her small daughter. The article stated, "Anthony's defense team says the child drowned accidently in a family pool."

I have never seen "accidently" used in proper writing (and in fact, my spell checker tells me it's wrong). Shouldn't the term be "accidentally"? I checked Grammar Girl, but she didn't have a post on this.

[CathyCA]

I'm not Wilson, but I am a grammar geek and a spelling bee, too.

While it seems that the much preferred spelling of the word is "accidentally," Merriam-Webster also lists "accidently" as a secondary spelling.

Oxford redirects from "accidently" to "No exact results found for 'accidently' in the dictionary. Did you mean accidental? Did you mean accidentally?"

I would think that "accidently" was an unfortunate spelling error that the proofreader accidentally didn't catch.