What is "aaronic"

Aaronic \Aa*ron"ic\ ([asl]*r[o^]n"[i^]k), Aaronical \Aa*ron"ic*al\ (-[i^]*kal), a. Pertaining to Aaron, the first high priest of the Jews.

a. 1 Pertaining to Aaron. (First attested in the mid 17^th century.) 2 Pertaining to or characteristic of a high priest; priestly. (First attested in the mid 17^th century.) 3 (context Mormonism English) Of or pertaining to the lower order of priests. (First attested in the early 19^th century.)