The Collaborative International Dictionary of English v.0.48:

Strap \Strap\, n. [OE. strope, AS. stropp, L. stroppus,
   struppus, perhaps fr. Gr. ? a band or cord, fr. ? to twist,
   to turn (cf. Strophe). Cf. Strop a strap, a piece of
   rope.]
   1. A long, narrow, pliable strip of leather, cloth, or the
      like; specifically, a strip of thick leather used in
      flogging.
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            A lively cobbler that . . . had scarce passed a day
            without giving her [his wife] the discipline of the
            strap.                                --Addison.
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   2. Something made of such a strip, or of a part of one, or a
      combination of two or more for a particular use; as, a
      boot strap, shawl strap, stirrup strap.
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   3. A piece of leather, or strip of wood covered with a
      suitable material, for sharpening a razor; a strop.
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   4. A narrow strip of anything, as of iron or brass.
      Specifically:
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      (a) (Carp. & Mach.) A band, plate, or loop of metal for
          clasping and holding timbers or parts of a machine.
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      (b) (Naut.) A piece of rope or metal passing around a
          block and used for fastening it to anything.
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   5. (Bot.)
      (a) The flat part of the corolla in ligulate florets, as
          those of the white circle in the daisy.
      (b) The leaf, exclusive of its sheath, in some grasses.
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   6. A shoulder strap. See under Shoulder.
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   Strap bolt, a bolt of which one end is a flat bar of
      considerable length.

   Strap head (Mach.), a journal box, or pair of brasses,
      secured to the end of a connecting rod by a strap. See
      Illust. of Gib and key, under Gib.

   Strap hinge, a hinge with long flaps by which it is
      fastened, as to a door or wall.

   Strap rail (Railroads), a flat rail formerly used.
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The Collaborative International Dictionary of English v.0.48:

Strap \Strap\, v. t. [imp. & p. p. Strapped; p. pr. & vb. n.
   Strapping.]
   1. To beat or chastise with a strap.
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   2. To fasten or bind with a strap. --Cowper.
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   3. To sharpen by rubbing on a strap, or strop; as, to strap a
      razor.
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WordNet (r) 3.0 (2006):

strap
    n 1: an elongated leather strip (or a strip of similar material)
         for binding things together or holding something in
         position
    2: hanger consisting of a loop of leather suspended from the
       ceiling of a bus or train; passengers hold onto it
    3: a band that goes over the shoulder and supports a garment or
       bag [syn: strap, shoulder strap]
    4: whip consisting of a strip of leather used in flogging
    v 1: tie with a strap [ant: unstrap]
    2: beat severely with a whip or rod; "The teacher often flogged
       the students"; "The children were severely trounced" [syn:
       flog, welt, whip, lather, lash, slash, strap,
       trounce]
    3: sharpen with a strap; "strap a razor"
    4: secure (a sprained joint) with a strap