Practice Tests: Synonyms - Five tests using synonyms. Answers included. - http://www.edict.com.hk/vlc/vocabsyn/FramesSyn1.htm
Kidport: Synonyms - Includes a definition and quiz about synonyms. - http://www.kidport.com/Grade3/LanguageArts/Synonyms.htm
Word Study Skills: Synonyms - Definition, pictures, and an interactive practice. Also includes games using synonyms. - http://www.manatee.k12.fl.us/sites/elementary/palmasola/synonyms.htm