Os·si·ning 
(ŏsĭ-nĭng) Formerly Sing Sing (sĭng sĭng′)
(ŏsĭ-nĭng) Formerly Sing Sing (sĭng sĭng′) A village of southeast New York north of New York City on the Hudson River. It is the site of Sing Sing Correctional Facility, a maximum security prison founded in 1825.