Earthenware and terra cotta (Latin terra cocta ‘cooked earth’) are too rough for when the vicar comes for tea. That’s the time to bring out the fine translucent ceramics. Porcelain fits the bill, refined, delicate and civilised as it is. No earth in its etymology, just French porcelaine from Italian porcellana, the name of the Venus shell, the cowrie, its polished surface the very model of chinaware’s smooth perfection.
But porcellana owes its origin to Latin porcellus, diminutive of porcus, a pig. Now it’s easy to see where pork comes from or how a porcupine is a spiny pig (porcus + spina), but porcelain and pigs?
Stop reading at this point if you are embarrassed by explicit reference to matters sexual. Instead you could look up porcus 2 in OLD which coyly says ‘(see quot.)’, omitting a translation.