The Collaborative International Dictionary of English v.0.48:

Parricide \Par"ri*cide\, n. [F., fr. L. parricida; pater father
   + caedere to kill. See Father, Homicide, and cf.
   Patricide.]
   [1913 Webster]
   1. Properly, one who murders one's own father; in a wider
      sense, one who murders one's father or mother or any
      ancestor.
      [1913 Webster]

   2. [L. parricidium.] The act or crime of murdering one's own
      father or any ancestor.
      [1913 Webster]

WordNet (r) 3.0 (2006):

parricide
    n 1: someone who kills his or her parent
    2: the murder of your own father or mother

Moby Thesaurus II by Grady Ward, 1.0:

19 Moby Thesaurus words for "parricide":
   aborticide, fratricide, fungicide, genocide, germicide, herbicide,
   homicide, infanticide, insecticide, matricide, microbicide,
   patricide, pesticide, regicide, rodenticide, sororicide, suicide,
   uxoricide, vermicide



Bouvier's Law Dictionary, Revised 6th Ed (1856):

PARRICIDE, civil law. One who murders his father; it is applied, by
extension, to one who murders his mother, his brother, his sister, or his
children. The crime committed by such person is also called parricide. Merl.
Rep. mot Parricide; Dig. 48, 9, 1, 1. 3, 1. 4.
     2. This offence is defined almost in the same words in the penal code
of China. Penal Laws of China, B. 1, s. 2, Sec. 4.
     3. The criminal was punished by being scourged, and afterwards sewed in
a sort of sack, with a dog, a cock, a viper, and an ape, and then thrown
into the sea, or into a river; or if there were no water, he was thrown in
this manner to wild beasts. Dig. 48, 9, 9; C. 9, 17, 1, 1. 4, 18, 6; Bro.
Civ; Law, 423; Wood's Civ. Law, B. 3, c. 10, s. 9.
     4. By the laws of France parricide is the crime of him who murders his
father or mother, whether they, be the legitimate, natural or adopted
parents of the individual, or the murder of any other legitimate ascendant.
Code Penal, art. 297. This crime is there punished by the criminal's being
taken to the place of execution without any other garment than his shirt,
barefooted, and with his head covered with a black veil. He is then exposed
on the scaffold while an officer of the court reads his sentence to the
spectators; his right hand is then cut off, and he is immediately put to
death. Id. art. 13.
     5. The common law does not define this crime, and makes no difference
between its punishment, and the punishment of murder. 1 Hale's P. C. 380;
Prin. Penal Law, c. 18, Sec. 8, p. 243; Dalloz, Dict. mot Homicide.