Webster's Revised Unabridged Dictionary · 1913

Ichthus

Ichthus (ik"thus) , noun

[Greek 'ichqy`s.]

In early Christian and ecclesiastical art, an emblematic fish, or the Greek word for fish, which combined the initials of the Greek words Ihsoy^s, Christo`s, Qeoy^ Gio`s Swth`r, Jesus, Christ, Son of God, Savior.