The Collaborative International Dictionary of English v.0.48:

Lamb's-quarters \Lamb's-quar"ters\, n. (Bot.)
   A name given to several common weedy European plants of the
   Goosefoot family, introduced into N. America, and sometimes
   used as pot herbs, as Chenopodium album and Atriplex
   patulsa.

   Note: It is sometimes collected from the wild and eaten as a
         vegetable

   Syn: lamb's quarters, pigweed, wild spinach, Chenopodium
        album.
        [1913 Webster + WordNet 1.5]