Lacerta

1 :  a genus (the type of the family Lacertidae) of lizards formerly including nearly all known lizards but now restricted to certain typical Old World forms — see green lizard, sand lizard

2 astronomy :  a northern constellation that is visible between the constellations of Andromeda and Cygnus and that is represented by the figure of a lizard The constellation Lacerta, the lizard, resides between the well-known patterns of Cygnus, the Swan, and Queen Cassiopeia, yet few people are aware of it. That's probably because the reptile's brightest stars are only fourth magnitude, and it rests in the midst of the Milky Way band among a multitude of faint stars. — Tulsa World, 10 Oct. 2004