Dolores is the Spanish word for "sorrows" — the title of the Virgin Mary as Nuestra Señora de los Dolores (Our Lady of Sorrows), referring to her seven sorrows. The English diminutive Lola also derives from Dolores.
Dolores peaked at #67 in the U.S. in 1929. Dolores Huerta (born 1930), the American labor leader and civil rights activist, is the most consequential bearer.
Dolores 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 Dolores reduce to 7, The Seeker. This is a traditional interpretive system, not a factual claim about the name.