So much later, I learned that this is the shape of the letter shin [], — Vulcan salute

"For what would soon become known as the Vulcan salute, I borrowed a hand symbol from Orthodox Judaism. During the High Holiday services, the Kohanim (who are the priests) bless those in attendance. As they do, they extend the palms of both hands over the congregation, with thumbs outstretched and the middle and ring fingers parted so that each hand forms two vees. This gesture symbolizes the Hebrew letter shin [], the first letter in the word Shaddai, "Lord"; in the Jewish Qabala, shin also represents eternal Spirit."