The Collaborative International Dictionary of English v.0.48:

Serpent \Ser"pent\, n. [F., fr. L. serpens, -entis (sc. bestia),
   fr. serpens, p. pr. of serpere to creep; akin to Gr. ???,
   Skr. sarp, and perhaps to L. repere, E. reptile. Cf.
   Herpes.]
   1. (Zool.) Any reptile of the order Ophidia; a snake,
      especially a large snake. See Illust. under Ophidia.
      [1913 Webster]

   Note: The serpents are mostly long and slender, and move
         partly by bending the body into undulations or folds
         and pressing them against objects, and partly by using
         the free edges of their ventral scales to cling to
         rough surfaces. Many species glide swiftly over the
         ground, some burrow in the earth, others live in trees.
         A few are entirely aquatic, and swim rapidly. See
         Ophidia, and Fang.
         [1913 Webster]

   2. Fig.: A subtle, treacherous, malicious person.
      [1913 Webster]

   3. A species of firework having a serpentine motion as it
      passess through the air or along the ground.
      [1913 Webster]

   4. (Astron.) The constellation Serpens.
      [1913 Webster]

   5. (Mus.) A bass wind instrument, of a loud and coarse tone,
      formerly much used in military bands, and sometimes
      introduced into the orchestra; -- so called from its form.
      [1913 Webster]

   Pharaoh's serpent (Chem.), mercuric sulphocyanate, a
      combustible white substance which in burning gives off a
      poisonous vapor and leaves a peculiar brown voluminous
      residue which is expelled in a serpentine from. It is
      employed as a scientific toy.

   Serpent cucumber (Bot.), the long, slender, serpentine
      fruit of the cucurbitaceous plant Trichosanthes
      colubrina; also, the plant itself.

   Serpent eage (Zool.), any one of several species of
      raptorial birds of the genera Circaetus and Spilornis,
      which prey on serpents. They inhabit Africa, Southern
      Europe, and India. The European serpent eagle is
      Circaetus Gallicus.

   Serpent eater. (Zool.)
      (a) The secretary bird.
      (b) An Asiatic antelope; the markhoor.

   Serpent fish (Zool.), a fish (Cepola rubescens) with a
      long, thin, compressed body, and a band of red running
      lengthwise.

   Serpent star (Zool.), an ophiuran; a brittle star.

   Serpent's tongue (Paleon.), the fossil tooth of a shark; --
      so called from its resemblance to a tongue with its root.


   Serpent withe (Bot.), a West Indian climbing plant
      (Aristolochia odoratissima).

   Tree serpent (Zool.), any species of African serpents
      belonging to the family Dendrophidae.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Serpent \Ser"pent\, v. i. [imp. & p. p. Serpented; p. pr. &
   vb. n. Serpenting.]
   To wind like a serpent; to crook about; to meander. [R.] "The
   serpenting of the Thames." --Evelyn.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Serpent \Ser"pent\, v. t.
   To wind; to encircle. [R.] --Evelyn.
   [1913 Webster]

WordNet (r) 3.0 (2006):

serpent
    n 1: limbless scaly elongate reptile; some are venomous [syn:
         snake, serpent, ophidian]
    2: a firework that moves in serpentine manner when ignited
    3: an obsolete bass cornet; resembles a snake

Moby Thesaurus II by Grady Ward, 1.0:

101 Moby Thesaurus words for "serpent":
   Apollyon, Beelzebub, Benedict Arnold, Brutus, Judas,
   Judas Iscariot, Lucifer, Old Nick, Old Scratch, Quisling, Satan,
   alpenhorn, alphorn, althorn, alto horn, animal, archtraitor,
   ballad horn, baritone, bass horn, beast, betrayer, brass choir,
   brass wind, brass-wind instrument, brasses, bugle, bugle horn,
   clarion, cockatrice, conniver, conspirator, conspirer, cornet,
   cornet-a-pistons, corno di caccia, cornopean, cur, diablo, dog,
   double agent, double-bell euphonium, double-crosser, double-dealer,
   euphonium, fiend, helicon, horn, hound, hunting horn, hyena,
   informer, insect, intrigant, intriguer, key trumpet, lituus, lur,
   machinator, mellophone, mongrel, ophicleide, ophidian,
   orchestral horn, pig, pit viper, plotter, pocket trumpet, polecat,
   post horn, quisling, rat, reptile, sackbut, saxhorn, saxtuba,
   schemer, sea snake, skunk, slide trombone, sliphorn, snake,
   sousaphone, swine, tenor tuba, timeserver, traitor, treasonist,
   trimmer, tromba, trombone, trumpet, tuba, turncoat, valve trombone,
   valve trumpet, varmint, vermin, viper, whelp, worm



Easton's 1897 Bible Dictionary:

Serpent
   (Heb. nahash; Gr. ophis), frequently noticed in Scripture. More
   than forty species are found in Syria and Arabia. The poisonous
   character of the serpent is alluded to in Jacob's blessing on
   Dan (Gen. 49:17; see Prov. 30:18, 19; James 3:7; Jer. 8:17).
   (See ADDER.)

     This word is used symbolically of a deadly, subtle, malicious
   enemy (Luke 10:19).

     The serpent is first mentioned in connection with the history
   of the temptation and fall of our first parents (Gen. 3). It has
   been well remarked regarding this temptation: "A real serpent
   was the agent of the temptation, as is plain from what is said
   of the natural characteristic of the serpent in the first verse
   of the chapter (3:1), and from the curse pronounced upon the
   animal itself. But that Satan was the actual tempter, and that
   he used the serpent merely as his instrument, is evident (1)
   from the nature of the transaction; for although the serpent may
   be the most subtle of all the beasts of the field, yet he has
   not the high intellectual faculties which the tempter here
   displayed. (2.) In the New Testament it is both directly
   asserted and in various forms assumed that Satan seduced our
   first parents into sin (John 8:44; Rom. 16:20; 2 Cor. 11:3, 14;
   Rev. 12:9; 20:2)." Hodge's System. Theol., ii. 127.