The Collaborative International Dictionary of English v.0.48:

Courtesy \Courte"sy\ (k[^u]rt"s[y^]), n. [See the preceding
   word.]
   An act of civility, respect, or reverence, made by women,
   consisting of a slight depression or dropping of the body,
   with bending of the knees. [Written also curtsy and
   curtsey.]
   [1913 Webster]

         The lady drops a courtesy in token of obedience, and
         the ceremony proceeds as usual.          --Golgsmith.
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The Collaborative International Dictionary of English v.0.48:

Courtesy \Cour"te*sy\ (k?r"t?-s?), n.; pl. Courtesies (-s?z).
   [OE. cortaisie, corteisie, courtesie, OF. curteisie,
   cortoisie, OF. curteisie, cortoisie, F. courtoisie, fr.
   curteis, corteis. See Courteous.]
   1. Politeness; civility; urbanity; courtliness.
      [1913 Webster]

            And trust thy honest-offered courtesy,
            With oft is sooner found in lowly sheds,
            With smoky rafters, than in tapestry walls
            And courts of princes, where it first was named,
            And yet is most pretended.            --Milton.
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            Pardon me, Messer Claudio, if once more
            I use the ancient courtesies of speech.
                                                  --Longfellow.
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   2. An act of civility or respect; an act of kindness or favor
      performed with politeness.
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            My lord, for your many courtesies I thank you.
                                                  --Shak.
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   3. Favor or indulgence, as distinguished from right; as, a
      title given one by courtesy.
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   Courtesy title, a title assumed by a person, or popularly
      conceded to him, to which he has no valid claim; as, the
      courtesy title of Lord prefixed to the names of the
      younger sons of noblemen.

   Syn: Politeness; urbanity; civility; complaisance;
        affability; courteousness; elegance; refinement;
        courtliness; good breeding. See Politeness.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Courtesy \Courte"sy\, v. i. [imp. & p. p. Courtesied
   (-s[i^]d); p. pr. & vb. n. Courtesying.]
   To make a respectful salutation or movement of respect; esp.
   (with reference to women), to bow the body slightly, with
   bending of the knes.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Courtesy \Courte"sy\, v. t.
   To treat with civility. [Obs.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

courtesy
    n 1: a courteous or respectful or considerate act
    2: a courteous or respectful or considerate remark
    3: a courteous manner [syn: courtesy, good manners] [ant:
       discourtesy, rudeness]

Moby Thesaurus II by Grady Ward, 1.0:

107 Moby Thesaurus words for "courtesy":
   act of courtesy, act of grace, act of kindness, admiration,
   adoration, affability, amenity, amiability, apotheosis,
   appreciation, approbation, approval, attention, attentiveness, awe,
   benefaction, benefit, benevolence, benignity, blessing,
   breathless adoration, ceremony, chivalry, civility, clubbability,
   clubbishness, clubbism, comity, communicativeness,
   companionability, compatibility, complaisance, congeniality,
   considerateness, consideration, cordiality, correct deportment,
   courteousness, courtliness, deference, deification, discourtesy,
   dispensation, duty, elegance, esteem, estimation, etiquette,
   exaggerated respect, familiarity, favor, fondness for society,
   formality, friendliness, gallantry, geniality, good behavior,
   good citizenship, good deed, good manners, good offices, good turn,
   grace, graceful gesture, graciousness, great respect,
   gregariousness, hero worship, high regard, homage, honor,
   hospitality, idolatry, idolization, indulgence, intimacy,
   kind deed, kind offices, kindly act, kindness, labor of love,
   mercy, misbehavior, mitzvah, obligation, office, polite act,
   politeness, politesse, poor behavior, prestige, regard, respect,
   respectfulness, reverence, reverential regard, sanctioned behavior,
   service, sociability, sociableness, social grace, sociality,
   thoughtfulness, turn, urbanity, veneration, worship



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

COURTESY, OR CURTESY, Scotch law. A right which vests in the husband, and is
in the nature of a life-rent. It is a counterpart of the terce. Courtesy
requires, 1st. That there shall have been a living child born of the
marriage, who is heir of the wife, or who, if surviving, would have been
entitled to succeed. 2d. That the wife shall have succeeded to the subjects
in question as heir either of line, or of talzie, or of provision. 1 Bell's
Com. 61; 2 Ersk. 9, 53. See Curtesy.