Steward, like Vincent said.
"New York State Census, 1855," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:K6QN-ZQL : 13 March 2018), Steward Boorn in household of Calvin Boorn, Decatur, Otsego, New York, United States; citing p. , line #26, family #34, county clerk offices, New York; FHL microfilm 869,024.
Find A Grave, database and images (https://www.findagrave.com : accessed 01 August 2018), memorial page for Pvt Stewart L. Boorn (3 Mar 1841–28 Sep 1908), Find A Grave Memorial no. 96408344, citing Oakwood Cemetery, Allegan, Allegan County, Michigan, USA ; Maintained by gravehound club (contributor 47349888) .
"United States Civil War Soldiers Index, 1861-1865," database, FamilySearch (https://familysearch.org/ark:/61903/1:1:FS8F-GJZ : 4 December 2014), Steward L. Boorn, , Company , 50th Regiment, New York Engineers, Union; citing NARA microfilm publication M551 (Washington D.C.: National Archives and Records Administration, n.d.), roll 12; FHL microfilm 882,068.