What is the origin of pellucid?

English pellucid comes from the Latin adjective pellūcidus (the usual Latin spelling is perlūcidus) “very clear, transparent.” The Latin adjective lūcidus is thoroughly naturalized in English lucid, but the Latin prefix and preposition per- is worth explanation. In Latin per- is used to intensify adjectives, adverbs, and verbs, e.g., perbonus “very good, excellent,” perbrevis “very short,” perbene “very well,” perbellē “very charmingly,” and percelebrāre “to make thoroughly known.” The Greek prefix and preposition perí- serves the same purpose, as in Periklês (c495-429 b.c.), the Athenian statesman, from the adjective perikleês “very famous.” Pellucid entered English in the 17th century.