The Collaborative International Dictionary of English v.0.48:

Maguey \Mag"uey\, n. [Sp. maguey, Mexican maguei and metl.]
   (Bot.)
   Any of several species of Agave, such as the century
   plant (Agave Americana), a plant requiring many years to
   come to maturity and blossoming only once before dying; and
   the Agave atrovirens, a Mexican plant used especially for
   making pulque, the source of the colorless Mexican liquor
   mescal; and the cantala (Agave cantala), a Philippine
   plant yielding a hard fibre used in making coarse twine. See
   Agave.
   [1913 Webster + WordNet 1.5]

   2. A hard fibre used in making coarse twine, derived from the
      Philippine Agave cantala (Agave cantala); also called
      cantala.
      [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Mescal \Mes*cal"\, n. [Sp.]
   A distilled liquor prepared in Mexico from a species of
   agave. See Agave.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Agave \A*ga"ve\ ([.a]*g[=a]"v[-e]), prop. n. [L. Agave, prop.
   name, fr. Gr. 'agayh`, fem. of 'agayo`s illustrious, noble.]
   (Bot.)
   A genus of plants (order Amaryllidaceae) of which the chief
   species is the maguey or century plant (Agave Americana),
   wrongly called Aloe. It takes from ten to seventy years,
   according to climate, to attain maturity, when it produces a
   gigantic flower stem, sometimes forty feet in height, and
   perishes. The juice has purgative and diuretic properties.
   The fermented juice is the pulque of the Mexicans;
   distilled, it yields mescal. A strong thread and a tough
   paper are made from the leaves, and the wood has many uses.
   [1913 Webster]

WordNet (r) 3.0 (2006):

mescal
    n 1: a small spineless globe-shaped cactus; source of mescal
         buttons [syn: mescal, mezcal, peyote, Lophophora
         williamsii]
    2: a colorless Mexican liquor distilled from fermented juices of
       certain desert plants of the genus Agavaceae (especially the
       century plant)