Meaning: a unisex name with two possible meanings. As a masculine name it could possibly be derived from Greek pallo meaning "to brandish". It's the name of several figures in Greek mythology, including a Titan.
As a feminine name it possibly means "maiden" or "young woman". It was the name of a daughter of Triton, the Greek god of the sea, who was a foster parent to Athena, the Greek goddess of wisdom, craft, and war, raising her alongside his own daughter. Pallas and Athena were good friends but during a friendly fight Zeus got involved and Pallas was wounded and ended up dying. Athena was very saddened by this, creating a wooden palladium of her and taking on her name as an epithet, Pallas Athena.