Hyphen:

It is a punctuation mark(-) used:

to form a compound from two or more other words:

Hard-hearted

Fork-lift truck

mother-to-be

to form a compound from a prefix and a proper name:

Pre-Raphaelite

Pre-European

when writing compound numbers between 21 and 99 in words:

Seventy-three

Thirty-one

sometimes in British English to separate a prefix ending in a vowel from a word beginning with the same vowel:

Co-operate

Pre-eminent