ΙΧΘΥΣ (Ichthys) is a backronym/acrostic for “Ίησοῦς Χριστός, Θεοῦ Υἱός, Σωτήρ”, (Iēsous Christos, Theou Yios, Sōtēr), which translates into English as “Jesus Christ, Son of God, Saviour”.
According to tradition, ancient Christians, during their persecution by the Roman Empire in the first few centuries after Christ, used the fish symbol to mark meeting places and tombs, or to distinguish friends from foes.
According to one ancient story, when a Christian met a stranger in the road, the Christian sometimes drew one arc of the simple fish outline in the dirt. If the stranger drew the other arc, both believers knew they were in good company. Here is the modern equivalent of that practice.
A wonderful bookmark to remind you continually of the history of the Christian faith.