WordNet (r) 3.0 (2006):

FWS
    n 1: an agency in the Department of the Interior that conserves
         and protects fish and wildlife and their habitats; assesses
         the environmental impact of pesticides and nuclear power
         site and hydroelectric dams and thermal pollution [syn:
         United States Fish and Wildlife Service, US Fish and
         Wildlife Service, FWS]

V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

FWS
       Folding White Space (RFC 1822)