Ellipsis and Em Dash

Ellipsis is represented in any piece of writing by a row of three periods or full stops (...). At times, it may overlap with the use of em dash (—).

Ellipsis is useful for omitting certain words in long speech writing, citations or quotations. When using ellipsis, however, the writer must be careful not to change the meaning of what the speaker is actually saying. This is a basic journalistic rule and ethical practice for any kind of writing. When ellipsis is used at the end of a sentence, it usually signifies something is 'to be continued ...'. If used somewhere between a sentence, it is considered an omission to shorten a sentence, often to remove words that are not critical to the objective point at hand. For example:

Before
Jane went about looking for the dog again and again, but was unable to find it.

After
Jane went about looking for the dog again ... but was unable to find it.

According to the MLA and AP style guideline, ellipsis should precede and proceed with a space for correct usage as shown above. There is a tendency for many writers to omit the space after a word, and this is not a correct usage following the standard style guides.

Em dash is represented by a longer dash (—), and should not be mistaken as figure dash (-) or en dash (–). Figure dash is used as a hyphen and en dash in a range, for example 'three to ten people' or 3–10 people.

Em dash is used in two ways, one as a break between a continuing sentence and the other at the end of sentence.

When used as a break between a continuing sentence, it sets off from the parenthetical information to indicate a break in character thought or speech. For example:

Every single thing we do—big or small—is significant in the sight of God.

When facing tough situations, the best thing to do is to first know God’s will through His word—the Bible.

When used at the end of a sentence, it usually refers to an aposiopesis—a sentence deliberately broken off and left unfinished which ending is supplied by your imagination or to give impression of unwillingness or inability to continue. For example:

"Get out, or else—!"

According to the MLA and AP style guideline, the em dash should not precede or proceed with a space for correct usage as shown above.