Sammy (n.) Look up Sammy at Dictionary.com
British slang for "U.S. soldier in World War I," 1918, a reference to Uncle Sam.
A Sammie may be defined as an American soldier as he appears in an English newspaper or a French cinema. It is a name he did not invent, does not like, never uses and will not recognize. ["Stars & Stripes," March 29, 1918]