The Collaborative International Dictionary of English v.0.48:

Abattoir \A`bat`toir"\ ([.a]`b[.a]t`tw[aum]r"), n.; pl.
   Abattoirs (-tw[aum]rz"). [F., fr. abattre to beat down. See
   Abate.]
   A public slaughterhouse for cattle, sheep, etc.
   [1913 Webster]

WordNet (r) 3.0 (2006):

abattoir
    n 1: a building where animals are butchered [syn: abattoir,
         butchery, shambles, slaughterhouse]