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What is the name of this symbol.

Minus, Dash, hyphen all dependent on usage.

From wikipedia:
The hyphen ( ‐ ) is a punctuation mark used to join words and to separate syllables of a single word. It should not be confused with dashes ( –, —, ― ), which are longer and have different uses, and with the minus sign ( − ) which is also longer. The use of hyphens is called hyphenation.