E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Ivory Gate of Dreams (The).
Dreams which delude pass through this gate, those which come true pass through the Gate of Horn. This fancy depends upon two puns: ivory in Greek is elphas, and the verb elephairo means to cheat with empty hopes; the Greek for horn is keras, and the verb karano means to accomplish.