“vermilion” or “vermillion”?

Question

Which one has primacy in English: "vermilion" or "vermillion" (as a color) ? Both have entries in various dictionaries. Is the difference concerned with AmE/BrE ?

Answer 1

It appears that the single-L spelling is more popular on both sites of the pond, according to the British National Corpus and the Corpus of Contemporary American English:

              BNC   COCA

 vermilion     43    197
 vermillion     3     34

This is excluding proper names. If we include them, the picture doesn't change dramatically:

                        BNC   COCA

 vermilion/Vermilion     50    327
 vermillion/Vermillion    5    139

Answer 2

According to Webster's Third New International Dictionary of the English Language, vermilion or vermillion is derived from,

[ME vermilioun, fr. OF vermeillon, fr. vermeil, adj., bright red, fr. LL vermiculus kermes (scale from which red dyestuff is derived), fr. L, little worm, dim. of vermis worm -- more at WORM]

There may be something involved with the distinction of between l/ll in the derivation from ME/OF.

Interesting too that there are several cities in the United States that use both the l/ll spellings.

Here is an Ngram as well that clearly favors the single 'l' spelling: