Dervla is from the Irish Deirbhile — daughter of the poet, daughter of song from Irish der (daughter) + file (poet). Dervla is one of the Irish feminine names — central to traditional Irish Catholic heritage.
Dervla 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 Dervla reduce to 8, The Visionary. This is a traditional interpretive system, not a factual claim about the name.