Eostre (Old English Ēostre, attested in Bede's De temporum ratione, 725 CE) was the Anglo-Saxon goddess of spring, dawn, and rebirth — celebrated in the Anglo-Saxon month of Eosturmonath (April). Jacob Grimm reconstructed a Continental Germanic counterpart Ostara in Deutsche Mythologie (1835); her sacred animal was the hare. The modern Easter egg and Easter Bunny are believed to descend from her cult.
Eostre 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 Eostre reduce to 1, The Leader. This is a traditional interpretive system, not a factual claim about the name.