The hyphen (- )'s a punctuation mark. It's used both to join words and also to separate syllables of a single word. It's often confused with dashes (–, —, ― ), which are longer and have different uses, and with the minus sign (− ) which's also longer. (When typing, some writers use two consecutive hyphens to represent a dash for speed or if a proper dash character isn't available.) The use of hyphens's called hyphenation. Customs of usage in English… (More on Hyphen)