One of the highest angelic orders, traditionally represented in Christian art with six wings and often associated with fiery or red coloration.
A seraph belongs to the highest of the traditional nine choirs of angels. In Western Christian imagery seraphim are often represented with six wings, sometimes with little or no visible body, and may be colored red to signify their fiery association.
Etymology
From Hebrew seraph, usually connected with the idea of burning or fiery beings; plural seraphim.
Sculptor Notes
Seraphim are structurally different from ordinary winged human angels. In carved ornament the six-wing arrangement can become almost heraldic or geometric, which makes them especially useful in vaults, altar surrounds, rays of glory, and architectural relief.
References
https://www.metmuseum.org/exhibitions/listings/2018/heavenly-bodies/exhibition-galleries-met-fifth-avenue; https://www.nga.gov/artworks/41676-madonna-and-child-saints-and-angels