The Collaborative International Dictionary of English v.0.48:

Discourse \Dis*course"\, n. [L. discursus a running to and fro,
   discourse, fr. discurrere, discursum, to run to and fro, to
   discourse; dis- + currere to run: cf. F. discours. See
   Course.]
   1. The power of the mind to reason or infer by running, as it
      were, from one fact or reason to another, and deriving a
      conclusion; an exercise or act of this power; reasoning;
      range of reasoning faculty. [Obs.]
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            Difficult, strange, and harsh to the discourses of
            natural reason.                       --South.
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            Sure he that made us with such large discourse,
            Looking before and after, gave us not
            That capability and godlike reason
            To fust in us unused.                 --Shak.
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   2. Conversation; talk.
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            In their discourses after supper.     --Shak.
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            Filling the head with variety of thoughts, and the
            mouth with copious discourse.         --Locke.
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   3. The art and manner of speaking and conversing.
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            Of excellent breeding, admirable discourse. --Shak.
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   4. Consecutive speech, either written or unwritten, on a
      given line of thought; speech; treatise; dissertation;
      sermon, etc.; as, the preacher gave us a long discourse on
      duty.
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   5. Dealing; transaction. [Obs.]
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            Good Captain Bessus, tell us the discourse
            Betwixt Tigranes and our king, and how
            We got the victory.                   --Beau. & Fl.
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The Collaborative International Dictionary of English v.0.48:

Discourse \Dis*course"\, v. i. [imp. & p. p. Discoursed; p.
   pr. & vb. n. Discoursing.]
   1. To exercise reason; to employ the mind in judging and
      inferring; to reason. [Obs.] "Have sense or can
      discourse." --Dryden.
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   2. To express one's self in oral discourse; to expose one's
      views; to talk in a continuous or formal manner; to hold
      forth; to speak; to converse.
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            Bid me discourse, I will enchant thine ear. --Shak.
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   3. To relate something; to tell. --Shak.
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   4. To treat of something in writing and formally.
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The Collaborative International Dictionary of English v.0.48:

Discourse \Dis*course"\, v. t.
   1. To treat of; to expose or set forth in language. [Obs.]
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            The life of William Tyndale . . . is sufficiently
            and at large discoursed in the book.  --Foxe.
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   2. To utter or give forth; to speak.
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            It will discourse most eloquent music. --Shak.
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   3. To talk to; to confer with. [Obs.]
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            I have spoken to my brother, who is the patron, to
            discourse the minister about it.      --Evelyn.
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WordNet (r) 3.0 (2006):

discourse
    n 1: extended verbal expression in speech or writing
    2: an address of a religious nature (usually delivered during a
       church service) [syn: sermon, discourse, preaching]
    3: an extended communication (often interactive) dealing with
       some particular topic; "the book contains an excellent
       discussion of modal logic"; "his treatment of the race
       question is badly biased" [syn: discussion, treatment,
       discourse]
    v 1: to consider or examine in speech or writing; "The author
         talks about the different aspects of this question"; "The
         class discussed Dante's `Inferno'" [syn: discourse, talk
         about, discuss]
    2: carry on a conversation [syn: converse, discourse]
    3: talk at length and formally about a topic; "The speaker
       dissertated about the social politics in 18th century
       England" [syn: hold forth, discourse, dissertate]