Winston is from the Old English Wīne's tūn — friend's town. The use of Winston as a feminine first name is part of the broader 21st-century American naming trend.
Winston 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 Winston reduce to 6, The Nurturer. This is a traditional interpretive system, not a factual claim about the name.