The Collaborative International Dictionary of English v.0.48:

Prince \Prince\, n. [F., from L. princeps, -cipis, the first,
   chief; primus first + capere to take. See Prime, a., and
   Capacious.]
   1. The one of highest rank; one holding the highest place and
      authority; a sovereign; a monarch; -- originally applied
      to either sex, but now rarely applied to a female.
      --Wyclif (Rev. i. 5).
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            Go, Michael, of celestial armies prince. --Milton.
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            Queen Elizabeth, a prince admirable above her sex.
                                                  --Camden.
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   2. The son of a king or emperor, or the issue of a royal
      family; as, princes of the blood. --Shak.
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   3. A title belonging to persons of high rank, differing in
      different countries. In England it belongs to dukes,
      marquises, and earls, but is given to members of the royal
      family only. In Italy a prince is inferior to a duke as a
      member of a particular order of nobility; in Spain he is
      always one of the royal family.
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   4. The chief of any body of men; one at the head of a class
      or profession; one who is pre["e]minent; as, a merchant
      prince; a prince of players. "The prince of learning."
      --Peacham.
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   Prince-Albert coat, a long double-breasted frock coat for
      men.

   Prince of the blood, Prince consort, Prince of
   darkness. See under Blood, Consort, and Darkness.

   Prince of Wales, the oldest son of the English sovereign.


   Prince's feather (Bot.), a name given to two annual herbs
      (Amarantus caudatus and Polygonum orientale), with
      apetalous reddish flowers arranged in long recurved
      panicled spikes.

   Prince's metal, Prince Rupert's metal. See under Metal.

   Prince's pine. (Bot.) See Pipsissewa.
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The Collaborative International Dictionary of English v.0.48:

Darkness \Dark"ness\, n.
   1. The absence of light; blackness; obscurity; gloom.
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            And darkness was upon the face of the deep. --Gen.
                                                  i. 2.
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   2. A state of privacy; secrecy.
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            What I tell you in darkness, that speak ye in light.
                                                  --Matt. x. 27.
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   3. A state of ignorance or error, especially on moral or
      religious subjects; hence, wickedness; impurity.
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            Men loved darkness rather than light, because their
            deeds were evil.                      --John. iii.
                                                  19.
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            Pursue these sons of darkness: drive them out
            From all heaven's bounds.             --Milton.
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   4. Want of clearness or perspicuity; obscurity; as, the
      darkness of a subject, or of a discussion.
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   5. A state of distress or trouble.
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            A day of clouds and of thick darkness. --Joel. ii.
                                                  2.
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   Prince of darkness, the Devil; Satan. "In the power of the
      Prince of darkness." --Locke.

   Syn: Darkness, Dimness, Obscurity, Gloom.

   Usage: Darkness arises from a total, and dimness from a
          partial, want of light. A thing is obscure when so
          overclouded or covered as not to be easily perceived.
          As tha shade or obscurity increases, it deepens into
          gloom. What is dark is hidden from view; what is
          obscure is difficult to perceive or penetrate; the eye
          becomes dim with age; an impending storm fills the
          atmosphere with gloom. When taken figuratively, these
          words have a like use; as, the darkness of ignorance;
          dimness of discernment; obscurity of reasoning; gloom
          of superstition.
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WordNet (r) 3.0 (2006):

Prince of Darkness
    n 1: (Judeo-Christian and Islamic religions) chief spirit of
         evil and adversary of God; tempter of mankind; master of
         Hell [syn: Satan, Old Nick, Devil, Lucifer,
         Beelzebub, the Tempter, Prince of Darkness]