The Collaborative International Dictionary of English v.0.48:

Lacerta \La*cer"ta\, n. [L. lacertus the arm.]
   A fathom. [Obs.] --Domesday Book.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Lacerta \La*cer"ta\, n. [L. a lizard. See Lizard.]
   1. (Zool.) A genus of lizards. See Lizard.
      [1913 Webster]

   Note: Formerly it included nearly all the known lizards. It
         is now restricted to certain diurnal Old World species,
         like the green lizard (Lacerta viridis) and the sand
         lizard (Lacerta agilis), of Europe.
         [1913 Webster]

   2. (Astron.) The Lizard, a northern constellation.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Lacerta
    n 1: type genus of the Lacertidae [syn: Lacerta, genus
         Lacerta]