An Arel, Ar'el, or Er'el, more commonly referred to in the plural as "the Erelim", are a rank of angels in Jewish Kabbala and Christian religion. The name is seen to mean "the valiant/courageous". They are generally seen as the third highest rank of divine beings/angels below God.
A specific Arel, or the erelim, are also referenced in other modern mysticism, in various ways, like the various Kabbalistic traditions, and elsewhere.
There may be an etymological relationship between the Arelim and the angel Ariel.