Cassia comes from the aromatic cassia spice tree and has ancient Greek and Latin usage.
Cassia arrives draped in the scent of ancient spice routes. The name comes directly from the Latin "cassia," which in turn derives from the Greek "kassia" and ultimately from the Hebrew "qetsi'ah" (קְצִיעָה), meaning "to strip the bark" — a reference to the cassia tree, a species of cinnamon-like plant whose aromatic bark was one of the most prized commodities of the ancient world. Cassia appears in Psalm 45 among the royal perfumes of a king's robes, and it was one of the ingredients in the sacred anointing oil prescribed in Exodus, placing the name in the very heart of biblical fragrance and ritual.
Cassia is also the feminine form of Cassius, the Latin family name of the Roman gens Cassia, best known through Gaius Cassius Longinus, one of the conspirators against Julius Caesar. On the feminine side, the name stands entirely independent, associated in Byzantine history with Kassia (or Cassia) of Constantinople, a remarkable 9th-century abbess and hymnographer — one of the few named female composers of the Byzantine period — whose Troparion for Holy Wednesday is still sung in Orthodox churches today. Her story, which involves Emperor Theophilos and a sharp-tongued retort that cost her a royal marriage, has become one of the great romantic legends of Byzantine history.
In modern use, Cassia has attracted parents drawn to botanical names with genuine ancient pedigree. It sounds like a cousin of Cassandra and Cassidy but carries its own distinct aromatic identity. Its appearance as a character name in Ally Condie's dystopian novel "Matched" (2010) introduced it to a new generation of readers, nudging it toward wider contemporary use without ever making it feel trendy or overexposed.