The Collaborative International Dictionary of English v.0.48:

Formality \For*mal"i*ty\, n.; pl. Formalities. [Cf. F.
   formalit['e].]
   1. The condition or quality of being formal, strictly
      ceremonious, precise, etc.
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   2. Form without substance.
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            Such [books] as are mere pieces of formality, so
            that if you look on them, you look though them.
                                                  --Fuller.
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   3. Compliance with formal or conventional rules; ceremony;
      conventionality.
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            Nor was his attendance on divine offices a matter of
            formality and custom, but of conscience.
                                                  --Atterbury.
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   4. An established order; conventional rule of procedure;
      usual method; habitual mode.
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            He was installed with all the usual formalities.
                                                  --C.
                                                  Middleton.
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   5. pl. The dress prescribed for any body of men, academical,
      municipal, or sacerdotal. [Obs.]
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            The doctors attending her in their formalities as
            far as Shotover.                      --Fuller.
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   6. That which is formal; the formal part.
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            It unties the inward knot of marriage, . . . while
            it aims to keep fast the outward formality.
                                                  --Milton.
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   7. The quality which makes a thing what it is; essence.
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            The material part of the evil came from our father
            upon us, but the formality of it, the sting and the
            curse, is only by ourselves.          --Jer. Taylor.
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            The formality of the vow lies in the promise made to
            God.                                  --Bp.
                                                  Stillingfleet.
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   8. (Scholastic. Philos.) The manner in which a thing is
      conceived or constituted by an act of human thinking; the
      result of such an act; as, animality and rationality are
      formalities.
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WordNet (r) 3.0 (2006):

formality
    n 1: a requirement of etiquette or custom; "a mere formality"
         [syn: formality, formalities]
    2: a manner that strictly observes all forms and ceremonies;
       "the formality of his voice made the others pay him close
       attention" [syn: formality, formalness] [ant:
       informality]
    3: compliance with formal rules; "courtroom formality"