The Collaborative International Dictionary of English v.0.48:
Pur \Pur\, v. i. [imp. & p. p. Purred; p. pr. & vb. n.
   Purring.] [Of imitative origin; cf. Prov. G. purren.]
   To utter a low, murmuring, continued sound, as a cat does
   when pleased. [Written also purr.]
   [1913 Webster]
The Collaborative International Dictionary of English v.0.48:
Pur \Pur\, v. t.
   To signify or express by purring. --Gray.
   [1913 Webster]
The Collaborative International Dictionary of English v.0.48:
Pur \Pur\, n.
   The low, murmuring sound made by a cat to express contentment
   or pleasure. [Written also purr.]
   [1913 Webster]
Hitchcock's Bible Names Dictionary (late 1800's):
Pur, Purim, lot
Bouvier's Law Dictionary, Revised 6th Ed (1856):
PUR. A corruption of the French word par, by or for. It is frequently used
in old French law phrases; as, pur autre vie. It is also used in the
composition of words, as purparty, purlieu, purview.