Pilar is the Spanish word for "pillar" — referring specifically to Our Lady of the Pillar (Nuestra Señora del Pilar), the patroness of Aragon and the Hispanic world.
Pilar is one of the most distinctive Spanish girl names — short, strong, with deep religious roots. The character Pilar in Hemingway's For Whom the Bell Tolls (1940) is one of the most memorable women in American literature.
Pilar 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 Pilar reduce to 2, The Peacemaker. This is a traditional interpretive system, not a factual claim about the name.