WordNet (r) 3.0 (2006):

Aaron
    n 1: United States professional baseball player who hit more
         home runs than Babe Ruth (born in 1934) [syn: Aaron,
         Henry Louis Aaron, Hank Aaron]
    2: (Old Testament) elder brother of Moses and first high priest
       of the Israelites; created the golden calf

Easton's 1897 Bible Dictionary:

Aaron
   the eldest son of Amram and Jochebed, a daughter of Levi (Ex.
   6:20). Some explain the name as meaning mountaineer, others
   mountain of strength, illuminator. He was born in Egypt three
   years before his brother Moses, and a number of years after his
   sister Miriam (2:1,4; 7:7). He married Elisheba, the daughter of
   Amminadab of the house of Judah (6:23; 1 Chr. 2:10), by whom he
   had four sons, Nadab and Abihu, Eleazar and Ithamar. When the
   time for the deliverance of Isarael out of Egypt drew nigh, he
   was sent by God (Ex. 4:14,27-30) to meet his long-absent
   brother, that he might co-operate with him in all that they were
   required to do in bringing about the Exodus. He was to be the
   "mouth" or "prophet" of Moses, i.e., was to speak for him,
   because he was a man of a ready utterance (7:1,2,9,10,19). He
   was faithful to his trust, and stood by Moses in all his
   interviews with Pharaoh.

     When the ransomed tribes fought their first battle with Amalek
   in Rephidim, Moses stood on a hill overlooking the scene of the
   conflict with the rod of God in his outstretched hand. On this
   occasion he was attended by Aaron and Hur, his sister's husband,
   who held up his wearied hands till Joshua and the chosen
   warriors of Israel gained the victory (17:8-13).

     Afterwards, when encamped before Sinai, and when Moses at the
   command of God ascended the mount to receive the tables of the
   law, Aaron and his two sons, Nadab and Abihu, along with seventy
   of the elders of Israel, were permitted to accompany him part of
   the way, and to behold afar off the manifestation of the glory
   of Israel's God (Ex. 19:24; 24:9-11). While Moses remained on
   the mountain with God, Aaron returned unto the people; and
   yielding through fear, or ignorance, or instability of
   character, to their clamour, made unto them a golden calf, and
   set it up as an object of worship (Ex. 32:4; Ps. 106:19). On the
   return of Moses to the camp, Aaron was sternly rebuked by him
   for the part he had acted in this matter; but he interceded for
   him before God, who forgave his sin (Deut. 9:20).

     On the mount, Moses received instructions regarding the system
   of worship which was to be set up among the people; and in
   accordance therewith Aaron and his sons were consecrated to the
   priest's office (Lev. 8; 9). Aaron, as high priest, held
   henceforth the prominent place appertaining to that office.

     When Israel had reached Hazeroth, in "the wilderness of
   Paran," Aaron joined with his sister Miriam in murmuring against
   Moses, "because of the Ethiopian woman whom he had married,"
   probably after the death of Zipporah. But the Lord vindicated
   his servant Moses, and punished Miriam with leprosy (Num. 12).
   Aaron acknowledged his own and his sister's guilt, and at the
   intercession of Moses they were forgiven.

     Twenty years after this, when the children of Israel were
   encamped in the wilderness of Paran, Korah, Dathan, and Abiram
   conspired against Aaron and his sons; but a fearful judgment
   from God fell upon them, and they were destroyed, and the next
   day thousands of the people also perished by a fierce
   pestilence, the ravages of which were only stayed by the
   interposition of Aaron (Num. 16). That there might be further
   evidence of the divine appointment of Aaron to the priestly
   office, the chiefs of the tribes were each required to bring to
   Moses a rod bearing on it the name of his tribe. And these,
   along with the rod of Aaron for the tribe of Levi, were laid up
   overnight in the tabernacle, and in the morning it was found
   that while the other rods remained unchanged, that of Aaron "for
   the house of Levi" budded, blossomed, and yielded almonds (Num.
   17:1-10). This rod was afterwards preserved in the tabernacle
   (Heb. 9:4) as a memorial of the divine attestation of his
   appointment to the priesthood.

     Aaron was implicated in the sin of his brother at Meribah
   (Num. 20:8-13), and on that account was not permitted to enter
   the Promised Land. When the tribes arrived at Mount Hor, "in the
   edge of the land of Edom," at the command of God Moses led Aaron
   and his son Eleazar to the top of that mountain, in the sight of
   all the people. There he stripped Aaron of his priestly
   vestments, and put them upon Eleazar; and there Aaron died on
   the top of the mount, being 123 years old (Num. 20:23-29. Comp.
   Deut. 10:6; 32:50), and was "gathered unto his people." The
   people, "even all the house of Israel," mourned for him thirty
   days. Of Aaron's sons two survived him, Eleazar, whose family
   held the high-priesthood till the time of Eli; and Ithamar, in
   whose family, beginning with Eli, the high-priesthood was held
   till the time of Solomon. Aaron's other two sons had been struck
   dead (Lev. 10:1,2) for the daring impiety of offering "strange
   fire" on the alter of incense.

     The Arabs still show with veneration the traditionary site of
   Aaron's grave on one of the two summits of Mount Hor, which is
   marked by a Mohammedan chapel. His name is mentioned in the
   Koran, and there are found in the writings of the rabbins many
   fabulous stories regarding him.

     He was the first anointed priest. His descendants, "the house
   of Aaron," constituted the priesthood in general. In the time of
   David they were very numerous (1 Chr. 12:27). The other branches
   of the tribe of Levi held subordinate positions in connection
   with the sacred office. Aaron was a type of Christ in his
   official character as the high priest. His priesthood was a
   "shadow of heavenly things," and was intended to lead the people
   of Israel to look forward to the time when "another priest"
   would arise "after the order of Melchizedek" (Heb. 6:20). (See MOSES.)


Hitchcock's Bible Names Dictionary (late 1800's):

Aaron, a teacher; lofty; mountain of strength