The Collaborative International Dictionary of English v.0.48:

Enhancement \En*hance"ment\, n.
   The act of increasing, or state of being increased;
   augmentation; aggravation; as, the enhancement of value,
   price, enjoyments, crime.
   [1913 Webster]

WordNet (r) 3.0 (2006):

enhancement
    n 1: an improvement that makes something more agreeable [syn:
         enhancement, sweetening]

Moby Thesaurus II by Grady Ward, 1.0:

109 Moby Thesaurus words for "enhancement":
   Great Leap Forward, accelerando, acceleration, advance,
   advancement, aggrandizement, aggravation, amelioration, amendment,
   amplification, annoyance, ascent, augmentation, ballyhoo,
   beefing-up, bettering, betterment, big talk, blowing up, blowup,
   boost, burlesque, caricature, complement, concentration,
   condensation, consolidation, contentiousness, deepening,
   deliberate aggravation, deterioration, dilatation, dilation,
   embittering, embitterment, enlargement, enrichment, eugenics,
   euthenics, exacerbation, exaggerating, exaggeration, exasperation,
   excess, exorbitance, expansion, explosion, extravagance, extreme,
   furtherance, grandiloquence, headway, heating-up, heightening,
   huckstering, hyperbole, hyperbolism, improvement, increase,
   inflation, information explosion, inordinacy, intensification,
   irritation, lift, magnification, melioration, mend, mending,
   overemphasis, overestimation, overkill, overstatement, pickup,
   population explosion, preferment, prodigality, profuseness,
   progress, progression, promotion, provocation, puffery, puffing up,
   recovery, redoubling, reinforcement, restoration, revival, rise,
   sensationalism, sharpening, souring, speedup, step-up,
   strengthening, stretching, superlative, tall talk, tightening,
   touting, travesty, upbeat, uplift, upping, upswing, uptrend,
   upward mobility, worsening



The Jargon File (version 4.4.7, 29 Dec 2003):

enhancement
 n.

    Common marketroid-speak for a bug fix. This abuse of language is a
    popular and time-tested way to turn incompetence into increased revenue. A
    hacker being ironic would instead call the fix a feature ? or perhaps
    save some effort by declaring the bug itself to be a feature.


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

enhancement
enhanced

    1. A change intended to make a product better in
   some way, e.g. new functions, faster, or occasionally more
   compatible with other systems.  Enhancements to hardware
   components, especially integrated circuits often mean they
   are smaller and less demanding of resources.  Sadly, this is
   almost never true of software enhancements.

   Examples include Digital Enhanced Cordless
   Telecommunications, Enhanced Capabilities Port, Enhanced
   Directory Service, Enhanced Dynamic Random Access Memory,
   Enhanced Graphics Adapter, Enhanced IDE, Enhanced
   Integrated Drive Electronics, enhanced parallel port,
   Enhanced Small Disk Interface, List Enhanced, Privacy
   Enhanced Mail.

   2. Marketroid-speak for a bug fix.  This abuse of language
   is a popular and time-tested way to turn incompetence into
   increased revenue.  A hacker being ironic would instead call
   the fix a feature, or perhaps save some effort by declaring
   "That's not a bug, that's a feature!".

   [Jargon File]

   (1998-04-04)