A creative spelling of Cassie, a diminutive of Cassandra, the Greek prophetic name.
Cassye is a creative spelling of Cassie, itself a familiar diminutive of Cassandra. That means it sits inside the Greek prophetic name family, but with a lighter and more playful surface.
The altered spelling gives the name a modern decorative look while preserving the soft sound that made Cassie popular in the first place. Cassye feels youthful, friendly, and slightly stylized, like a nickname that has been made into a full name. It carries the mythological shadow of Cassandra in the background, but in everyday use it reads as approachable and contemporary. That mix of ancient root and casual charm gives the name its appeal.