The hyphen is a punctuation mark used to join words and to separate syllables of a single word. The use of hyphens is called hyphenation.
The hyphen should not be confused with dashes, which are longer and have different uses, or with the minus sign, which is also longer in some contexts. Some words can be hyphenated in different places and you can use this website to find out where. Also reffered to as syllable counter and divider.