Skullcap, Kippah, or Yarmulke?

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“A campaign was launched in France calling on all citizens to don the Jewish skullcap on Friday [January 16],” reported that day’s Algemeiner, “after the Marseille chief rabbi urged fellow residents to avoid wearing kippot, out of fear of anti-Semitic terror. . . . The campaign called on citizens to put on the yarmulke at 10 a.m. on Friday in a coordinated effort.”

Skullcap, kippah (or kipah), yarmulke: three different words, all in one short paragraph, for the same round Jewish head covering. Are they interchangeable?