--- what does it means?

[MsNyree]

Ellipsis means something that is omitted, but what does --- means?

Example:

And when you get through to your listeners—when you engage their hearts and minds—make sure you give them a worthwhile message, not torrents of words that are quickly forgotten.

[beascarpetta]

it's called "parenthesis"
hope this is what you wanted to know

[mykwyner]

Although there is no such "official" punctuation mark, many modern writers use the dash to indicate a pause longer than a comma, but not a period.