www.alphadictionary.com

How many three-letter alphabet sequences appear in English words? Probably more than you'd think. How many of four?

Can you name a double eponym, that is, someone with two words originating from his name? I know one, and I'd be excited to learn another.

Answers will be posted in a few days, although you probably know how to research the first question.

It depends on what you mean by "two words." I'll assume you don't mean a noun and a verb such as "vandal" and "vandalize" or units and phenomenon like "volt" and "voltage"
But here seem to be quite a few double eponyms:
Simon Bolivar -- Bolivia, the bolivar and the boliviano: the country, the currency in Venezuela and the currency in Bolivia

Luigi Galvani -- galvanize 1) Charge with electrical current, 2) To coat iron or steel with zinc by placing in an appropriate solution and passing current through the materials 3) arouse a crowd to concerted action

Knickerbocker (a family invented by Washington Irving) -- knickers 1) in the US knee-length trousers 2) in the UK women's underpants

John Loudon McAdam -- macadam and tarmac

Before I stop I'd like to mention Bacchus (Roman) and Dionysus (Greek), two names for the same god whose names gave us bacchanalla and dionysian.

But there are more in the eponym list on this website.

Without researching the matter, the only word I can think of with a four-letter alphabet sequence is understudy.

One "double eponym" is July and caesarean, both (supposedly) named after Julius Caesar.

Great stuff! I was thinking of Sir Robert Peel. Along with 'bobby' there's the Irish/British slang term 'peeler'.

As far as the alphabet goes:

abcoulomb
ecderon
defy
afghani (the coin - not capitalized)
sighing
hijack
calmness
statuvolism
hydroxyzine

gymnopaedic
overstuff

Thank you all.

We go on and turn the corner with
analyzable
And that adds another 4-letter sequence