How are 'arcane' and 'abstruse' different?

Are they words in common usage?

What would they normally be used to describe?

A vocabulary book of mine says "an archetype is usually something that precedes something else" and gives "Plato is the archetype of all phiosophers" as an example. I looked up the word in two different dictionarys and they both seem to offer 'a perfect example of something' as the definition of an archetype.

Is the vocabulary book wrong?

Thank you in advance
See definitions and usage examples at:




"abstruse" and "arcane" are not very common in everyday English, but you may come across them in written English or hear them occasionally in more elevated conversation. (They're not the sort of words your average Joe would be very likely to use, and I guess a proportion of native speakers would not know what they meant.) I would have guessed that "arcane" is rarer than "abstruse", but Google stats indicate the opposite, which shows how much I know...
Thanks a lot!