Emily comes from the Latin Aemilia — the feminine of Aemilius, a Roman family name possibly from aemulus, meaning "rival" or "eager." The English form Emily took shape in the medieval period.
Emily was the most popular U.S. The poet Emily Dickinson (1830-1886) and Emily Brontë (Wuthering Heights) are major American literary bearers. Today Emily sits in the U.S. top 25.
Emily 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 Emily reduce to 1, The Leader. This is a traditional interpretive system, not a factual claim about the name.