An angel of the first order; usually portrayed as the winged head of a child WordNet 3.0 & Open English WordNet

A seraph is a celestial or heavenly being originating in Ancient Judaism. Wikipedia

Celestial being in Jewish and Christian mythology. Wikipedia Disambiguation

A six-winged angel; 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. A detailed description can be found at the beginning of Isaiah chapter 6. Wiktionary

Highest order of angels. Wiktionary (translation)