Oak \Oak\ ([=o]k), n. [OE. oke, ok, ak, AS. [=a]c; akin to
         D.
   eik, G. eiche, OHG. eih, Icel. eik, Sw. ek, Dan.
         eeg.]
   [1913 Webster]
   1. (Bot.) Any tree or shrub of
         the genus Quercus. The
         oaks
      have alternate leaves, often variously lobed,
         and
      staminate flowers in catkins. The fruit is a
         smooth nut,
      called an acorn, which is more or less
         inclosed in a
      scaly involucre called the cup or
         cupule. There are now
      recognized about three hundred
         species, of which nearly
      fifty occur in the United
         States, the rest in Europe,
      Asia, and the other parts
         of North America, a very few
      barely reaching the
         northern parts of South America and
      Africa. Many of
         the oaks form forest trees of grand
      proportions and
         live many centuries. The wood is usually
      hard and
         tough, and provided with conspicuous medullary
      rays,
         forming the silver grain.
      [1913 Webster]

   2. The
         strong wood or timber of the oak.
      [1913 Webster]

 
          Note: Among the true oaks in America are:

   {Barren
         oak}, or

   Black-jack, {Quercus
         nigra}.

   {Basket
         oak}, Quercus
         Michauxii.

   Black
         oak, {Quercus
         tinctoria}; -- called also yellow oak
      or
         quercitron
         oak.

   Bur oak
         (see under Bur.),
         Quercus
         macrocarpa; -- called
      also over-cup or
         mossy-cup oak.


           Chestnut oak,
         Quercus Prinus
         and
         Quercus
         densiflora.

   Chinquapin oak (see under
         Chinquapin),
         Quercus
         prinoides.

   {Coast live
         oak}, Quercus
         agrifolia, of California; -- also
     
         called enceno.

  
         Live oak (see under
         Live),
         Quercus virens,
         the best of
      all for shipbuilding;
         also, Quercus
         Chrysolepis, of
      California.

  
         Pin oak. Same as {Swamp
         oak}.

   Post oak,
         {Quercus
         obtusifolia}.

   Red
         oak, Quercus
         rubra.

  
         Scarlet oak,
         Quercus
         coccinea.

   Scrub
         oak,
         Quercus
         ilicifolia, Quercus undulata, etc.
      

  
         Shingle oak,
         Quercus
         imbricaria.

   Spanish oak,
         Quercus
         falcata.

   Swamp Spanish oak, or

   {Pin
         oak}, Quercus
         palustris.

   Swamp white oak, {Quercus
         bicolor}.

   Water
         oak, Quercus
         aquatica.

  
         Water white oak,
         Quercus
         lyrata.

   Willow
         oak,
         Quercus
         Phellos.
      [1913 Webster] Among the true oaks
         in Europe are:

   Bitter oak, or

   Turkey oak,
         Quercus Cerris
         (see Cerris).

   {Cork
         oak}, {Quercus
         Suber}.

   English white oak, Quercus Robur.

  
         Evergreen oak,


           Holly oak, or

  
         Holm oak,
         Quercus Ilex.

  
         Kermes oak, {Quercus
         coccifera}.


           Nutgall oak,
         Quercus
         infectoria.
      [1913
         Webster]

   Note: Among plants called oak, but not of the
         genus
         Quercus, are:

  
         African oak, a
         valuable timber tree ({Oldfieldia
     
         Africana}).

   Australian oak or She oak, any tree of
         the genus
      Casuarina (see Casuarina).

  
         Indian oak, the teak
         tree (see Teak).

  
         {Jerusalem
         oak}. See under Jerusalem.

   {New
         Zealand oak}, a
         sapindaceous tree (Alectryon excelsum).

  
         Poison oak, a shrub
         once not distinguished from poison
         ivy,
      but now restricted to Rhus
         toxicodendron or
         Rhus
         diversiloba.

   Silky oak or {Silk-bark
         oak}, an Australian tree
      (Grevillea
         robusta).
    
          [1913 Webster]

   Green oak, oak wood colored green by
         the growth of the
      mycelium of certain fungi.

  
         Oak apple, a large,
         smooth, round gall produced on the
  
            leaves of the American red oak by a gallfly ({Cynips
   
           confluens}). It is green and pulpy when young.

   {Oak
         beauty} (Zool.), a British geometrid moth ({Biston
     
         prodromaria}) whose larva feeds on the oak.

   {Oak
         gall}, a gall found on the oak. See 2d Gall.

   {Oak
         leather} (Bot.), the mycelium of a fungus which forms
     
         leatherlike patches in the fissures of oak wood.

   {Oak
         pruner}. (Zool.) See Pruner, the insect.

  
         {Oak
         spangle}, a kind of gall produced on the oak by the
     
         insect Diplolepis lenticularis.

   Oak wart,
         a
         wartlike gall on the twigs of an oak.

   The Oaks, one
         of the three great annual English horse races
      (the
         Derby and St. Leger being the others). It was
     
         instituted in 1779 by the Earl of Derby, and so called
    
          from his estate.

   To sport one's oak, to be "not at
         home to visitors,"
      signified by closing the outer
         (oaken) door of one's
      rooms. [Cant, Eng. Univ.]
    
          [1913 Webster]