What is the meaning of Seraph?

A burning serpent, often winged, with human hands and sometimes feet; one of God's entourage. On Earth, they strike with burning poison; in Heaven, with burning coal. A description can be found at the beginning of Isaiah chapter 6.

A six-winged angel; one of the highest choir or order of angels in Christian angelology, ranked above cherubim, and below God. They are the 5th-highest order of angels in Jewish angelology.

Source: wiktionary.org