The Collaborative International Dictionary of English v.0.48:

Teach \Teach\ (t[=e]ch), v. t. [imp. & p. p. Taught (t[add]t);
   p. pr. & vb. n. Teaching.] [OE. techen, imp. taughte,
   tahte, AS. t[=ae]cean, imp. t[=ae]hte, to show, teach, akin
   to t[=a]cn token. See Token.]
   1. To impart the knowledge of; to give intelligence
      concerning; to impart, as knowledge before unknown, or
      rules for practice; to inculcate as true or important; to
      exhibit impressively; as, to teach arithmetic, dancing,
      music, or the like; to teach morals.
      [1913 Webster]

            If some men teach wicked things, it must be that
            others should practice them.          --South.
      [1913 Webster]

   2. To direct, as an instructor; to manage, as a preceptor; to
      guide the studies of; to instruct; to inform; to conduct
      through a course of studies; as, to teach a child or a
      class. "He taught his disciples." --Mark ix. 31.
      [1913 Webster]

            The village master taught his little school.
                                                  --Goldsmith.
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   3. To accustom; to guide; to show; to admonish.
      [1913 Webster]

            I shall myself to herbs teach you.    --Chaucer.
      [1913 Webster]

            They have taught their tongue to speak lies. --Jer.
                                                  ix. 5.
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   Note: This verb is often used with two objects, one of the
         person, the other of the thing; as, he taught me Latin
         grammar. In the passive construction, either of these
         objects may be retained in the objective case, while
         the other becomes the subject; as, I was taught Latin
         grammar by him; Latin grammar was taught me by him.
         [1913 Webster]

   Syn: To instruct; inform; inculcate; tell; guide; counsel;
        admonish. See the Note under Learn.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Teaching \Teach"ing\, n.
   The act or business of instructing; also, that which is
   taught; instruction.
   [1913 Webster]

   Syn: Education; instruction; breeding. See Education.
        [1913 Webster]

WordNet (r) 3.0 (2006):

teaching
    n 1: the profession of a teacher; "he prepared for teaching
         while still in college"; "pedagogy is recognized as an
         important profession" [syn: teaching, instruction,
         pedagogy]
    2: a doctrine that is taught; "the teachings of religion"; "he
       believed all the Christian precepts" [syn: teaching,
       precept, commandment]
    3: the activities of educating or instructing; activities that
       impart knowledge or skill; "he received no formal education";
       "our instruction was carefully programmed"; "good classroom
       teaching is seldom rewarded" [syn: education,
       instruction, teaching, pedagogy, didactics,
       educational activity]

Moby Thesaurus II by Grady Ward, 1.0:

118 Moby Thesaurus words for "teaching":
   a belief, adage, ana, analects, aphorism, apothegm,
   article of faith, assignment, autodidactic, axiom, belief, byword,
   canon, catchword, chalk talk, charge, coeducational,
   collected sayings, command, commission, credo, creed, cultural,
   current saying, dictate, dictum, didactic, direction, disciplinary,
   discourse, disquisition, distich, doctrine, dogma, edifying,
   educating, educational, educative, enlightening, epigram, exercise,
   exhortatory, exposition, expression, faith, gnome, golden saying,
   harangue, homework, homiletic, homily, hortatory, illuminating,
   informative, initiatory, injunction, instruction, instructive,
   introductory, lecture, lecture-demonstration, lecturing, lesson,
   maxim, moral, moral lesson, morality, moralization, mot, motto,
   object lesson, oracle, order, orthodoxy, phrase, pithy saying,
   preaching, preachment, precept, preceptive, prescript,
   prescription, principle, propaedeutic, proverb, proverbial saying,
   proverbs, recital, recitation, religion, religious belief,
   religious faith, saw, saying, self-teaching, sentence,
   sententious expression, sermon, set task, skull session, sloka,
   stock saying, sutra, system of beliefs, talk, task, tenet, text,
   theology, tradition, tuitionary, verse, wisdom, wisdom literature,
   wise saying, witticism, word, words of wisdom