Scout is from the Old French escouter (to listen, watch) — a modern English word-name. Boy Scouts of America (founded 1910). "Scout's honor" — the colloquial expression. Pawnee Scouts — historical US Army indigenous scouts.
Scout 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 Scout reduce to 6, The Nurturer. This is a traditional interpretive system, not a factual claim about the name.