Ichthys

This is the formal name for the “Jesus fish.”

It’s been dated back to the 2nd century. Historians speculate that it was used by Christians to safely identify each other during periods of persecution.

The etymology of the word is disputed, but one fascinating theory is that the acronym for the Greek phrase “Jesus Christ, Son of God, Savior” is “ἸΧΘΥΣ” which is very close to the Greek word for “fish” – “IKhThUS.”

It’s pronounced “ick-this.”