Today on Morning Joe, Mika Brzezinski quoted from a text and pronounced the word cache as "cash-ay." This is a common confusion.
Both cache, pronounced "cash," and cachet, pronounced "cash-ay," derive from the French cacher, "to hide." Cache has a direct route into English, a verb meaning "to conceal," as one secures food on a camping trip to keep it from raccoons and bears. As a noun, cache can be the place where the items are hidden or the items themselves.
Cachet comes from a different sense of cacher, "to press," which derives from the Latin cogere, also "to press." A cachet is a seal pressed on a document, attesting to its authenticity or official approval. From that sense the word has been extended to mean "a mark of distinction" or simply "prestige."