[1] : Easton's 1897 Bible Dictionary

abiathar
   father of abundance, or my father excels, the son of ahimelech
   the high priest. he was the tenth high priest, and the fourth in
   descent from eli. when his father was slain with the priests of
   nob, he escaped, and bearing with him the ephod, he joined
   david, who was then in the cave of adullam 1 sam. 22:20-23;
   23:6. he remained with david, and became priest of the party of
   which he was the leader 1 sam. 30:7. when david ascended the
   throne of judah, abiathar was appointed high priest 1 chr.
   15:11; 1 kings 2:26 and the "king's companion" 1 chr. 27:34.
   meanwhile zadok, of the house of eleazar, had been made high
   priest. these appointments continued in force till the end of
   david's reign 1 kings 4:4. abiathar was deposed the sole
   historical instance of the deposition of a high priest and
   banished to his home at anathoth by solomon, because he took
   part in the attempt to raise adonijah to the throne. the
   priesthood thus passed from the house of ithamar 1 sam.
   2:30-36; 1 kings 1:19; 2:26, 27. zadok now became sole high
   priest. in mark 2:26, reference is made to an occurrence in "the
   days of abiathar the high priest." but from 1 sam. 22, we learn
   explicitly that this event took place when ahimelech, the father
   of abiathar, was high priest. the apparent discrepancy is
   satisfactorily explained by interpreting the words in mark as
   referring to the life-time of abiathar, and not to the term of
   his holding the office of high priest. it is not implied in mark
   that he was actual high priest at the time referred to. others,
   however, think that the loaves belonged to abiathar, who was at
   that time lev. 24:9 a priest, and that he either himself gave
   them to david, or persuaded his father to give them.
   

[2] : Hitchcock's Bible Names Dictionary (late 1800's)

abiathar, excellent father; father of the remnant

Abiathar >> A Words
Abiathar, definition of term: Abiathar
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