Beyonce and Jay-Z's twins' names are a mystery no more -- at least it appears that way.

It seems Rumi and Sir Carter are the new additions to the family. We know that because the company run by Bey and Jay that owns the trademarks to their names filed legal docs Monday, June 26 -- right around the time the twins went home -- to secure rights to the names Rumi Carter and Sir Carter.

The docs are filed by the same company that filed for a Blue Ivy trademark earlier this year.

The name Rumi appears to be an homage to a 13th century Persian poet by that name -- and Sir happens to be referenced in one of his most famous poems:

Bring the pure wine of
love and freedom.
But sir, a tornado is coming.
More wine, we'll teach this storm
A thing or two about whirling.

The trademarks are for fragrances, cosmetics, key chains, baby teething rings, strollers, mugs, water bottles, hair ribbons, playing cards, tote bags, sports balls, rattles and novelty items.

Short story ... Rumi and Sir are about to become part of the Carter empire.

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