Clementine is the feminine of Clement — from the Latin clemens, meaning "merciful," "mild," or "gentle." Several popes have borne the masculine name Clement. The small citrus fruit (the clementine, a type of mandarin orange) was named after Brother Clément, a French monk in Algeria who developed it in 1902.
Clementine has been rising rapidly in the U.S.
Clementine 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 Clementine reduce to 1, The Leader. This is a traditional interpretive system, not a factual claim about the name.