Gage is from the Old French gage (pledge, oath, security). Gage Creed — central character of Stephen King's Pet Sematary (1983); the toddler whose tragic death and resurrection drive the novel's horror; King has called it his most-frightening novel; the 1989 Mary Lambert film and 2019 Kevin Kölsch film adaptations made the character one of the most-iconic horror children in American fiction. Brent Gage — modern American figure. Gage County — Nebraska. Lily Gage — American character actress.
Gage 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 Gage reduce to 2, The Peacemaker. This is a traditional interpretive system, not a factual claim about the name.