The Collaborative International Dictionary of English v.0.48:

Technical \Tech"nic*al\, a. [Gr. ?, fr. ? an art, probably from
   the same root as ?, ?, to bring forth, produce, and perhaps
   akin to E. text: cf. F. technique.]
   Of or pertaining to the useful or mechanic arts, or to any
   science, business, or the like; specially appropriate to any
   art, science, or business; as, the words of an indictment
   must be technical. --Blackstone.
   [1913 Webster]

WordNet (r) 3.0 (2006):

technical
    adj 1: of or relating to technique or proficiency in a practical
           skill; "his technical innovation was his brushwork"; "the
           technical dazzle of her dancing" [syn: technical,
           proficient]
    2: characterizing or showing skill in or specialized knowledge
       of applied arts and sciences; "a technical problem"; "highly
       technical matters hardly suitable for the general public"; "a
       technical report"; "producing the A-bomb was a challenge to
       the technical people of this country"; "technical training";
       "technical language" [ant: nontechnical, untechnical]
    3: of or relating to a practical subject that is organized
       according to scientific principles; "technical college";
       "technological development" [syn: technical,
       technological]
    4: of or relating to or requiring special knowledge to be
       understood; "technical terminology"; "a technical report";
       "technical language" [syn: technical, expert]
    5: resulting from or dependent on market factors rather than
       fundamental economic considerations; "analysts content that
       the stock market is due for a technical rally"; "the fall is
       only a technical correction"
    n 1: a pickup truck with a gun mounted on it
    2: (basketball) a foul that can be assessed on a player or a
       coach or a team for unsportsmanlike conduct; does not usually
       involve physical contact during play [syn: technical foul,
       technical]

Moby Thesaurus II by Grady Ward, 1.0:

64 Moby Thesaurus words for "technical":
   accomplished, applied, at concert pitch, authoritative,
   back-burner, career, coached, complex, complicated, confined,
   conversant, detailed, dinky, disciplinary, dispensable, expert,
   feature, featured, finished, functional, immaterial, inappreciable,
   inconsequential, inconsiderable, industrial, inessential, inferior,
   initiate, initiated, insignificant, intricate, irrelevant,
   knowledgeable, limited, little, mechanical, minor, minute,
   negligible, nonessential, not vital, official, petit, polytechnic,
   practiced, prepared, primed, pro, professional, restricted,
   scholarly, scientific, skilled, small, specialist, specialistic,
   specialized, technicological, technological, trained, unessential,
   unimpressive, unnoteworthy, vocational



Bouvier's Law Dictionary, Revised 6th Ed (1856):

TECHNICAL. That which properly belongs to an art.
     2. In the construction of contracts, it is a general rule that
technical words are to be taken according to their approved and known use in
the trade in which the contract is entered into, or to which it relates,
unless they have manifestly been understood in another sense by the parties.
2 B. & P. 164; 6 T. R. 320; 3 Stark. Ev. 1036, and the article Construction.
     3. Words which do not of themselves denote that they are, used in a
technical sense, are to have their plain, popular, obvious and natural
meaning. 6 Watts & Serg. 114.
     4. The law, like other professions, has a technical language. "When a
mechanic speaks to me of the instruments and operations of his trade,", says
Mr. Wynne, Eunom. Dial. 2, s. 5, "I shall be as unlikely to comprehend him,
as he would me in the language of my profession, though we both of us spoke
English all the while. Is it wonderful then, if in systems of law, and
especially among the hasty recruits of commentators, you meet (to use Lord
Coke's expression) with a whole army of words that cannot defend themselves
in a grammatical war? Technical language, in all cases, is formed from the
most intimate knowledge of any art. One words stands for a great many, as it
is. always to be resolved into many ideas by definitions. It is, therefore,
unintelligible, because it is concise, and it is useful for the same
reason." Vide Language.