Correct name for hashtag is 'Octothorp', reveals Twitter
On the 10-year anniversary of using hashtags, Twitter revealed on Wednesday that the technically correct name for the symbol is 'Octothorp'. The word originated in the 1960s when a research company making telephone keypads claimed the "octo" part referred to eight points on the symbol, whereas "thorpe" was a tribute to Olympian Jim Thorpe. 