Ivory gate is a poetic image for the gate of false dreams. The phrase comes from classical tradition, where dreams are said to leave the underworld through an ivory gate and arrive in misleading or deceptive forms, unlike true dreams that pass through a horn gate. Poets use the image to suggest illusion, wishful thinking, or a vision that looks beautiful but cannot be trusted.
Example
Through the ivory gate my sleeping heart
sent a city of gold that vanished at dawn,
its towers bright as fire, its streets already lost.