The Collaborative International Dictionary of English v.0.48:

ace \ace\ adj.
   1. of the highest quality an ace reporter

   Syn: A-one, first-class, first-rate, super, tip-top,
        topnotch(predicate)
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

ace \ace\ v.
   to get a grade of "A"; as, to ace an exam. [Colloq.]
   [PJC]

The Collaborative International Dictionary of English v.0.48:

Ace \Ace\ ([=a]s), n.; pl. Aces ([=a]"s[e^]z). [OE. as, F. as,
   fr. L. as, assis, unity, copper coin, the unit of coinage.
   Cf. As.]
   [1913 Webster]
   1. A unit; a single point or spot on a card or die; the card
      or die so marked; as, the ace of diamonds.
      [1913 Webster]

   2. Hence: A very small quantity or degree; a particle; an
      atom; a jot.
      [1913 Webster]

            I 'll not wag an ace further.         --Dryden.
      [1913 Webster]

   3. (Sport) A single point won by a stroke, as in handball,
      rackets, etc.; in tennis, frequently, a point won by a
      service stroke.
      [Webster 1913 Suppl.]

   To bate an ace, to make the least abatement. [Obs.]

   Within an ace of, very near; on the point of. --W. Irving.
      [1913 Webster]

WordNet (r) 3.0 (2006):

ace
    adj 1: of the highest quality; "an ace reporter"; "a crack
           shot"; "a first-rate golfer"; "a super party"; "played
           top-notch tennis"; "an athlete in tiptop condition"; "she
           is absolutely tops" [syn: ace, A-one, crack,
           first-rate, super, tiptop, topnotch, top-notch,
           tops(p)]
    n 1: the smallest whole number or a numeral representing this
         number; "he has the one but will need a two and three to go
         with it"; "they had lunch at one" [syn: one, 1, I,
         ace, single, unity]
    2: one of four playing cards in a deck having a single pip on
       its face
    3: someone who is dazzlingly skilled in any field [syn: ace,
       adept, champion, sensation, maven, mavin,
       virtuoso, genius, hotshot, star, superstar, whiz,
       whizz, wizard, wiz]
    4: proteolytic enzyme that converts angiotensin I into
       angiotensin II [syn: angiotensin converting enzyme,
       angiotensin-converting enzyme, ACE]
    5: a major strategic headquarters of NATO; safeguards an area
       extending from Norway to Turkey [syn: Allied Command
       Europe, ACE]
    6: a serve that the receiver is unable to reach
    v 1: succeed at easily; "She sailed through her exams"; "You
         will pass with flying colors"; "She nailed her astrophysics
         course" [syn: breeze through, ace, pass with flying
         colors, sweep through, sail through, nail]
    2: score an ace against; "He aced his opponents"
    3: play (a hole) in one stroke
    4: serve an ace against (someone)

Moby Thesaurus II by Grady Ward, 1.0:

231 Moby Thesaurus words for "ace":
   A per se, I, air force, amigo, associate, atom, beaut, bedfellow,
   bedmate, best bower, bit, bomber pilot, bosom buddy, boss, bower,
   bowshot, brief span, buddy, bunkie, bunkmate, butty, camarade,
   cards, chamberfellow, champion, chief, chum, classmate,
   close quarters, close range, clubs, colleague, comate,
   combat pilot, commander, companion, company, compeer, comrade,
   confrere, consociate, consort, copartner, corker, crack,
   crackerjack, crony, crumb, dab, daisy, dandy, darb, dean, deck,
   deuce, diamonds, dilly, dole, dot, dram, dream, dribble, driblet,
   dummy, dwarf, earreach, earshot, face cards, farthing, fellow,
   fellow student, fighter pilot, first-rater, fleck, flush, flyboy,
   flyspeck, fragment, fugleman, full house, genius, girl friend,
   gobbet, good hand, gossip, grain, granule, great, groat, gunshot,
   hair, hair space, hairbreadth, hairsbreadth, hand, handful, head,
   hearts, higher-up, honey, humdinger, inch, iota, jack, joker, jot,
   killer-diller, king, knave, knockout, laureate, leader, left bower,
   little, little bit, little ways, lollapaloosa, lota, lulu,
   magician, mahatma, man of genius, master, master hand, mastermind,
   mate, messmate, military pilot, minim, minimum, minutiae, mite,
   modicum, molecule, monad, mote, naval pilot, no other, none else,
   nonpareil, nothing else, nought beside, nutshell, observer,
   old crony, one, one and only, ounce, pack, pair, pal, paragon,
   pard, pardner, particle, partner, past master, peach, pebble,
   picture cards, pinch, pip, pippin, pistol shot, pittance,
   playfellow, playing cards, playmate, point, practiced hand,
   principal, prodigy, queen, roommate, round, royal flush, rubber,
   ruff, ruler, sage, schoolfellow, schoolmate, scruple, senior,
   shipmate, short distance, short piece, short way, side partner,
   sidekick, singleton, skilled hand, smidgen, smitch, spades, span,
   speck, spitting distance, spoonful, spot, star, step, straight,
   suicide pilot, superior, superman, superstar, sweetheart, teammate,
   the greatest, the most, the nuts, thimbleful, tiny bit, tittle,
   top dog, topnotcher, trey, trick, trifling amount, trivia, trump,
   unit, virtuoso, whisker, whit, whiz, wizard, workfellow,
   yokefellow, yokemate



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

ACE
       Access Control Entry (AD, ACL)


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

ACE
       Actuator Control Electronics (Airbus, A380)


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

ACE
       Advanced Computing Environment (manufacturer)


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

ACE
       Adobe Color Engine (Adobe)


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

ACE
       ASCII Compatible Encoding (ASCII, Internet)


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

ACE
       Autonomous Computer Engine (WD)


The Free On-line Dictionary of Computing (30 December 2018):

ACE

   1. Advanced Computing Environment.

   2. Adaptive Communication Environment.