As a Greek, I feel the need to protest the corruption of the word cleistophobia (kleisto = closed) into claustrophobia.
Claus- sounds like the root of "to cry" (e.g. clausigelos = crying laughter), so a Greek reading claustrophobia thinks of people who are afraid of crying (though the proper rendering of a word composite with that meaning would be klauthmophobia).
Claustro- comes from Latin Claustrum, which shares the same root as the Greek word. Claustrophobia wasn’t a word in Latin or Greek though, it’s a modern hybrid.
