Named after Thornhill, the residence of Dr Henry Norman Barnett on Upper Newtownards Road. He was a specialist in ear, nose and throat medicine. Further biographical details are given in Knock, Knock... who was there? by Keith Haines (2014), pp. 58-66.
"Resolved – That the name Thornhill Parade be approved for a new street off Thornhill Park on the property of Mr. Joseph McMaster; also that the name Londonderry Park be disapproved for a new street off Knock Road on the property of Mr. F. W. Campbell". (7th May 1935).
On the recommendation of the City Surveyor, the committee approved of the name of Thornhill Parade for a new street in continuation of Thornhill Parade off Barnetts Rd, the property of the Irish Sailors and Soldiers Land Trust. (8th August 1950). “On the recommendation of the City surveyor and application from the Irish Sailors and Soldiers Land Trust for a name Thornhill Parade for New Street in continuation of Thornhill Parade was acceded to”. (21st August 1951).