A rather unusual and puzzling name. It may be tempting to explain it as containing French "de", but one would expect this to be followed by a space and there is no surname or place-name spelt *Norrton, with two RRs. A more likely explanation is as a portmanteau name consisting of three elements: DEN + ORR + TON. This development was built on the site of the former residence of the shipbuilder and politician Gustav Wolff (1834-1913). He named his house "The Den", a pun on his surname (wolves live in a den). The following two elements seem to come from the name of a property developer called Robert Orr Templeton. His name appears as a contact in a number of advertisements for property to let in East Belfast, including one mentioning Denorrton Park specifically in the Belfast Telegraph, Saturday 01/01/1927, p. 1.
"Resolved – That Mr. R. Orr Templeton be informed in reply to his application dated 8th inst., that the Committee cannot see their way to approve of the name Denorrton Park for new street on his property situate off Holywood Road, and request him to submit another name therefor". (15th June 1926)
"Submitted application, dated 25th inst., from Mr. R. Orr Templeton to have new street on his property situate off Holywood Road, named "Denorrton Park", and it was Resolved – That the application be granted." (30th November 1926).