ichthyscommon nounSyllable DecompositionichthysEtymologyexpandFrom Greek ikhthus meaning 'fish', acrostic of the Greek words iêsous christos theou uios sôtêr. The fish symbolizing Christ.Definition1. A word found on some Christian monuments, made up of the first letters of Jesus Christ, Son of God, Savior. Christians often referred to themselves under the emblem and name of fish, through a kind of wordplay.expand