Source : Webster's Revised Unabridged Dictionary (1913)

Pea \Pea\, n.; pl. {Peas}or {Pease}. [OE. pese, fr. AS. pisa, or
   OF. peis, F. pois; both fr. L. pisum; cf. Gr. ?, ?. The final
   s was misunderstood in English as a plural ending. Cf.
   {Pease}.]
   1. (Bot.) A plant, and its fruit, of the genus {Pisum}, of
      many varieties, much cultivated for food. It has a
      papilionaceous flower, and the pericarp is a legume,
      popularly called a pod.

   Note: When a definite number, more than one, is spoken of,
         the plural form peas is used; as, the pod contained
         nine peas; but, in a collective sense, the form pease
         is preferred; as, a bushel of pease; they had pease at
         dinner. This distinction is not always preserved, the
         form peas being used in both senses.

   2. A name given, especially in the Southern States, to the
      seed of several leguminous plants (species of {Dolichos},
      {Cicer}, {Abrus}, etc.) esp. those having a scar (hilum)
      of a different color from the rest of the seed.

   Note: The name pea is given to many leguminous plants more or
         less closely related to the common pea. See the
         Phrases, below.

   {Beach pea} (Bot.), a seashore plant, {Lathyrus maritimus}.
      

   {Black-eyed pea}, a West Indian name for {Dolichos
      sph[ae]rospermus} and its seed.

   {Butterfly pea}, the American plant {Clitoria Mariana},
      having showy blossoms.

   {Chick pea}. See {Chick-pea}.

   {Egyptian pea}. Same as {Chick-pea}.

   {Everlasting pea}. See under {Everlasting}.

   {Glory pea}. See under {Glory}, n.

   {Hoary pea}, any plant of the genus {Tephrosia}; goat's rue.
      

   {Issue pea}, {Orris pea}. (Med.) See under {Issue}, and
      {Orris}.

   {Milk pea}. (Bot.) See under {Milk}.

   {Pea berry}, a kind of a coffee bean or grain which grows
      single, and is round or pea-shaped; often used
      adjectively; as, pea-berry coffee.

   {Pea bug}. (Zo["o]l.) Same as {Pea weevil}.

   {Pea coal}, a size of coal smaller than nut coal.

   {Pea crab} (Zo["o]l.), any small crab of the genus
      {Pinnotheres}, living as a commensal in bivalves; esp.,
      the European species ({P. pisum}) which lives in the
      common mussel and the cockle.

   {Pea dove} (Zo["o]l.), the American ground dove.

   {Pea-flower tribe} (Bot.), a suborder ({Papilionace[ae]}) of
      leguminous plants having blossoms essentially like that of
      the pea. --G. Bentham.

   {Pea maggot} (Zo["o]l.), the larva of a European moth
      ({Tortrix pisi}), which is very destructive to peas.

   {Pea ore} (Min.), argillaceous oxide of iron, occurring in
      round grains of a size of a pea; pisolitic ore.

   {Pea starch}, the starch or flour of the common pea, which is
      sometimes used in adulterating wheat flour, pepper, etc.
      

   {Pea tree} (Bot.), the name of several leguminous shrubs of
      the genus {Caragana}, natives of Siberia and China.

   {Pea vine}. (Bot.)
      (a) Any plant which bears peas.
      (b) A kind of vetch or tare, common in the United States
          ({Lathyrus Americana}, and other similar species).

   {Pea weevil} (Zo["o]l.), a small weevil ({Bruchus pisi})
      which destroys peas by eating out the interior.

   {Pigeon pea}. (Bot.) See {Pigeon pea}.

   {Sweet pea} (Bot.), the annual plant {Lathyrus odoratus};
      also, its many-colored, sweet-scented blossoms.

Source : WordNet®

butterfly pea
     n 1: vine of tropical Asia having pinnate leaves and bright blue
          yellow-centered flowers [syn: {blue pea}, {Clitoria
          turnatea}]
     2: large-flowered wild twining vine of southeastern and central
        United States having pale blue flowers [syn: {Clitoria
        mariana}]
     3: large-flowered weakly twining or prostrate vine of New
        Jersey to tropical eastern North America, sometimes
        cultivated for its purple and white flowers [syn: {Centrosema
        virginianum}]