Mentioned in Isaiah 6:2,3,6,7. This word means fiery ones, in allusion, as is supposed, to their burning love. They are represented as "standing" above the King as he sat upon his throne, ready at once to minister unto him. Their form appears to have been human, with the addition of wings. (See ANGELS
.) This word, in the original, is used elsewhere only of the "fiery serpents" (Numbers 21:6,8; Deuteronomy 8:15; Compare Isaiah 14:29; 30:6) sent by God as his instruments to inflict on the people the righteous penalty of sin.
These dictionary topics are from M.G. Easton M.A., D.D., Illustrated Bible Dictionary, Third Edition, published by Thomas Nelson, 1897. Public Domain, copy freely.
Easton, Matthew George. "Entry for 'Seraphim'". "Easton's Bible Dictionary".