The Collaborative International Dictionary of English v.0.48:

Obelisk \Ob"e*lisk\, v. t. [imp. & p. p. Obelisked
   ([o^]b"[e^]*l[i^]skt); p. pr. & vb. n. Obelisking.]
   To mark or designate with an obelisk.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

obelisk \ob"e*lisk\ ([o^]b"[e^]*l[i^]sk), n. [L. obeliscus, Gr.
   'obeli`skos, dim. of 'obelo`s a spit, a pointed pillar: cf.
   F. ob['e]lisque.]
   1. An upright, four-sided pillar, gradually tapering as it
      rises, and terminating in a pyramid called pyramidion. It
      is ordinarily monolithic. Egyptian obelisks are commonly
      covered with hieroglyphic writing from top to bottom.
      [1913 Webster]

   2. (Print.) A mark of reference; -- called also dagger
      [[dagger]]. See Dagger, n., 2.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Dagger \Dag"ger\ (-g[~e]r), n. [Cf. OE. daggen to pierce, F.
   daguer. See Dag a dagger.]
   1. A short weapon used for stabbing. This is the general
      term: cf. Poniard, Stiletto, Bowie knife, Dirk,
      Misericorde, Anlace.
      [1913 Webster]

   2. (Print.) A mark of reference in the form of a dagger
      [[dagger]]. It is the second in order when more than one
      reference occurs on a page; -- called also obelisk.
      [1913 Webster]

   Dagger moth (Zool.), any moth of the genus Apatalea. The
      larv[ae] are often destructive to the foliage of fruit
      trees, etc.

   Dagger of lath, the wooden weapon given to the Vice in the
      old Moralities. --Shak.

   Double dagger, a mark of reference [[dag]] which comes next
      in order after the dagger.

   To look daggers, or To speak daggers, to look or speak
      fiercely or reproachfully.
      [1913 Webster]

WordNet (r) 3.0 (2006):

obelisk
    n 1: a stone pillar having a rectangular cross section tapering
         towards a pyramidal top
    2: a character used in printing to indicate a cross reference or
       footnote [syn: dagger, obelisk]

Moby Thesaurus II by Grady Ward, 1.0:

85 Moby Thesaurus words for "obelisk":
   antenna tower, arch, barbican, barrow, belfry, bell tower,
   boundary stone, brass, bust, cairn, campanile, cenotaph, colossus,
   column, cromlech, cross, cup, cupola, cyclolith, derrick, dolmen,
   dome, fire tower, footstone, grave, gravestone, headstone,
   hoarstone, inscription, lantern, lighthouse, marker, martello,
   martello tower, mast, mausoleum, megalith, memento, memorial,
   memorial arch, memorial column, memorial statue, memorial stone,
   menhir, minaret, monolith, monument, mound, necrology, obituary,
   observation tower, pagoda, pilaster, pillar, pinnacle, plaque,
   pole, prize, pylon, pyramid, reliquary, remembrance, ribbon,
   rostral column, shaft, shrine, skyscraper, spire, standpipe,
   steeple, stela, stone, stupa, tablet, television mast, testimonial,
   tomb, tombstone, tope, tour, tower, trophy, turret, water tower,
   windmill tower