Stella is the Latin word for "star." The English poet Sir Philip Sidney popularised the name in the 1580s with his sonnet sequence Astrophil and Stella — Latin and Greek for "star-lover and star." It has been continuously used in English ever since.
Stella is often associated with the Marian title Stella Maris ("Star of the Sea") in Catholic tradition. Today Stella sits in the U.S. top 40.
Stella does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Stella reduce to 6, The Nurturer. This is a traditional interpretive system, not a factual claim about the name.