07/06/2011 at 02:00 PM EDT
and fiancé Benjamin Millepied get an A-plus for the name they picked for their baby boy
Their son's name is Aleph, a source confirms to PEOPLE.
So what's in a name? Aleph is the first letter of the Hebrew alphabet, much like alpha is the first letter of the Greek alphabet. Aleph is the number 1 in Hebrew and can also be spelled "alef."
Its esoteric meaning in Judaic Kabbalah, as denoted in the theological treaty Sefer-ha-Bahir, relates to the origin of the universe, the "primordial one that contains all numbers."
Portman, 30, met choreographer Millepied on the set of Black Swan
, for which she later won an Oscar for Best Actress
Reporting by JOEY BARTOLOMEO