What is Archangel?

Legal Definition
An archangel /ˌɑːrkˈnəl/ is an angel of high rank. Beings that are very similar to archangels are found in a number of religious traditions; but the word "archangel" itself is usually associated with the Abrahamic religions.

The word archangel is derived from the Greek ἀρχάγγελος (arch- + angel, literally chief angel).
-- Wikipedia
Legal Definition
A strong angel investor with a successful history in investment. A consultant kept by angels to research and present opportunities.