means A person with whom you feel a deep, natural connection — emotionally, romantically, or spiritually — as if you were meant to find each other.

from A transparent compound of "soul" and "mate," both old Germanic words: "soul" (Old English sawol, the inner spirit) joined to "mate" (a companion, ultimately tied to the idea of sharing meat or a meal — one you eat with). The pairing is fairly modern, an 18th–19th-century coinage; the poet Samuel Taylor Coleridge is often credited with popularizing it when he mused that everyone needs a "soul-mate." The romantic notion behind it, though, is ancient — Plato's Symposium tells of humans split in two, forever seeking their other half.