The noun is one word, with no hyphen.
Historic means famous or important in history, as in “a historic occasion”, whereas historical can refer to anything that occurred in the past. So it’s a historical share price, not a historic one (and certainly not an historic one).
There’s no need to say “an historic moment” (or an historic anything). It’s a historic moment. Possibly because many years ago the H of historic wasn’t aspirated, it was customary to write “an historic” and now there is a misconceived notion that “an historic” is the right way to describe something terribly important. It’s not.
- A horde is a crowd or a mob.
- A hoard is an accumulated store of something, and the verb to hoard means to accumulate a store of something.