Omar is not derived from
Omar Khayyam OR the caliph. There is no way that the name
Omar can be derived from itself.
Omar Khayyam and the caliph
Umar are given as examples of well-known people with those names. The actual meaning of
Umar (
Omar) is "flourishing" or "populous".
Omar is also a biblical name with several meanings: "he that speaks", "bitter", "first born", and "disciple".