WordNet (r) 3.0 (2006):

Abel
    n 1: Norwegian mathematician (1802-1829) [syn: Abel, Niels
         Abel, Niels Henrik Abel]
    2: (Old Testament) Cain and Abel were the first children of Adam
       and Eve born after the Fall of Man; Abel was killed by Cain

V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

ABEL
       Advanced Boolean Expression Language


Easton's 1897 Bible Dictionary:

Abel
   (Heb. Hebhel), a breath, or vanity, the second son of Adam and
   Eve. He was put to death by his brother Cain (Gen. 4:1-16).
   Guided by the instruction of their father, the two brothers were
   trained in the duty of worshipping God. "And in process of time"
   (marg. "at the end of days", i.e., on the Sabbath) each of them
   offered up to God of the first-fruits of his labours. Cain, as a
   husbandman, offered the fruits of the field; Abel, as a
   shepherd, of the firstlings of his flock. "The Lord had respect
   unto Abel and his offering; but unto Cain and his offering he
   had not respect" (Gen. 4:3-5). On this account Cain was angry
   with his brother, and formed the design of putting him to death;
   a design which he at length found an opportunity of carrying
   into effect (Gen. 4:8,9. Comp. 1 John 3:12). There are several
   references to Abel in the New Testament. Our Saviour speaks of
   him as "righteous" (Matt. 23:35). "The blood of sprinkling" is
   said to speak "better things than that of Abel" (Heb. 12:24);
   i.e., the blood of Jesus is the reality of which the blood of
   the offering made by Abel was only the type. The comparison here
   is between the sacrifice offered by Christ and that offered by
   Abel, and not between the blood of Christ calling for mercy and
   the blood of the murdered Abel calling for vengeance, as has
   sometimes been supposed. It is also said (Heb. 11:4) that "Abel
   offered unto God a more excellent sacrifice than Cain." This
   sacrifice was made "by faith;" this faith rested in God, not
   only as the Creator and the God of providence, but especially in
   God as the great Redeemer, whose sacrifice was typified by the
   sacrifices which, no doubt by the divine institution, were
   offered from the days of Adam downward. On account of that
   "faith" which looked forward to the great atoning sacrifice,
   Abel's offering was accepted of God. Cain's offering had no such
   reference, and therefore was rejected. Abel was the first
   martyr, as he was the first of our race to die.

     Abel (Heb. 'abhel), lamentation (1 Sam. 6:18), the name given
   to the great stone in Joshua's field whereon the ark was "set
   down." The Revised Version, however, following the Targum and
   the LXX., reads in the Hebrew text _'ebhen_ (= a stone), and
   accordingly translates "unto the great stone, whereon they set
   down the ark." This reading is to be preferred.

     Abel (Heb. 'abhel), a grassy place, a meadow. This word enters
   into the composition of the following words:


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

Abel, vanity; breath; vapor


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

Abel, a city; mourning