Gertrude is from the Old Germanic gar (spear) + thrudh (strength). Saint Gertrude the Great (1256-c. Gertrude Stein (1874-1946) — American expatriate writer; her Paris salon at 27 rue de Fleurus hosted Picasso, Matisse, Hemingway, and Fitzgerald; "A rose is a rose is a rose" (Sacred Emily, 1913) is among the most-quoted lines in modernist poetry. Gertrude Ederle (1905-2003) — first woman to swim the English Channel (1926) — and she did it 2+ hours faster than any of the five men who had done it before. Gertrude — Queen of Denmark, Hamlet's mother.
Gertrude is a compound name. Its parts are gair + þrúðr — each an attested element with a recorded meaning of its own.
Gertrude 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 Gertrude reduce to 8, The Visionary. This is a traditional interpretive system, not a factual claim about the name.