Gwendolen combines the Welsh gwen (white, blessed) and dolen (ring, bow) — meaning "white ring" or "blessed circle." In Arthurian legend, Gwendolen was a queen.
Gwendolen Fairfax is the witty heroine of Oscar Wilde's The Importance of Being Earnest (1895).
Gwendolen 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.
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In Pythagorean numerology the letters of Gwendolen reduce to 9, The Giver. This is a traditional interpretive system, not a factual claim about the name.