720-783) was the wife of Pepin the Short and mother of Charlemagne — one of the most influential women of the Carolingian dynasty.
Bertrada is a compound name. Its parts are radŭ — each an attested element with a recorded meaning of its own.
Bertrada 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 Bertrada reduce to 6, The Nurturer. This is a traditional interpretive system, not a factual claim about the name.