Παντοκράτωρ / Pantokrator.

Greek monasteries.

In Eastern Christianity, the most widely used Christogram is a four-letter abbreviation, ICXC — a traditional abbreviation of the Greek words for "Jesus Christ" (the first and last letters of each of the words ΙΗΣΟΥΣ ΧΡΙΣΤΟΣ — written "IHCOYC XPICTOC" with a transliteration of the lunate sigma common in medieval Greek as "C"). On icons, this Christogram may be split: "IC" on the left of the image and "XC" on the right, most often with a bar above the letters, indicating that it is a sacred name. It is sometimes rendered as "ICXC NIKA", meaning "Jesus Christ Conquers." "ICXC" may also be seen inscribed on the Ichthys. In the traditional icon of Christ Pantokrator, Christ's right hand is shown in a pose that represents the letters IC, X, and C.

Ichtys (or Ikhthus). ἰχθύς / ΙΧΘΥΣ

This word means in ancient Greek "fish". The symbol of the Ikhthus is commonly represented with two intersecting arcs, in order to make it look like a fish. This symbol was a secret symbol used by the first Christians. The letters of the word fish bear in fact another meaning. Ikhthus is in reality a word formed from the first letters of several words:
"Jesus Christ, God's son, Savior" in ancient Greek "Ἰησοῦς Χριστός, Θεοῦ ͑Υιός, Σωτήρ" (to be pronounced: Iēsous Christos, Theou Huios, Sōtēr).

The symbol of the Ikhthus was also represented as a wheel (which represents the wheel of the gold chariot or the tiller of a boat). This symbol of a wheel contains the letters ΙΧΘΥΣ superimposed that result in a wheel with eight sticks.