The Collaborative International Dictionary of English v.0.48:

Prime \Prime\, n.
   1. The first part; the earliest stage; the beginning or
      opening, as of the day, the year, etc.; hence, the dawn;
      the spring. --Chaucer.
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            In the very prime of the world.       --Hooker.
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            Hope waits upon the flowery prime.    --Waller.
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   2. The spring of life; youth; hence, full health, strength,
      or beauty; perfection. "Cut off in their prime."
      --Eustace. "The prime of youth." --Dryden.
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   3. That which is first in quantity; the most excellent
      portion; the best part.
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            Give him always of the prime.         --Swift.
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   4. [F. prime, LL. prima (sc. hora). See Prime, a.] The
      morning; specifically (R. C. Ch.), the first canonical
      hour, succeeding to lauds.
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            Early and late it rung, at evening and at prime.
                                                  --Spenser.
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   Note: Originally, prime denoted the first quarter of the
         artificial day, reckoned from 6 a. m. to 6 p. m.
         Afterwards, it denoted the end of the first quarter,
         that is, 9 a. m. Specifically, it denoted the first
         canonical hour, as now. Chaucer uses it in all these
         senses, and also in the sense of def. 1, above.
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               They sleep till that it was pryme large.
                                                  --Chaucer.
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   5. (Fencing) The first of the chief guards.
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   6. (Chem.) Any number expressing the combining weight or
      equivalent of any particular element; -- so called because
      these numbers were respectively reduced to their lowest
      relative terms on the fixed standard of hydrogen as 1.
      [Obs. or Archaic]
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   7. (Arith.) A prime number. See under Prime, a.
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   8. An inch, as composed of twelve seconds in the duodecimal
      system; -- denoted by [']. See 2d Inch, n., 1.
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   Prime of the moon, the new moon at its first appearance.
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