Grammar Guide: The Difference Between a Hyphen and a Dash

Occasionally on the GRE or GMAT, you’ll see hyphens and dashes. How can you recognize them and use them properly?

There are two uses for a dash:

1. To indicate a break in thought.

Example: I forget which way to go- wait, now I remember!

Here the dash functions like a semicolon. Notice there is just ONE dash.

2. To set off a parenthetical phrase.

Example: My cousin Mary – whom you have never met – saw the movie “Gravity” last night.

Here the dashes function like commas setting apart non-essential information. Notice there are TWO dashes.

A hyphen and a dash look exactly the same, but are used differently:

Dash = Between words

Hyphen = Between syllables

Let’s look at an SC question involving this punctuation:

Archaeologists in Egypt have excavated a 5,000-year-old wooden hull that is the earliest surviving example of example of a “built” boat-in other words, a boat constructed out of planks fitted together-and that thus represents a major
advance, in terms of boat-building technology, over the dugout logs and reed vessels of more ancient vintage.

A. together-and that thus represents
B. together-and this has represented
C. together, and it represents
D. together that was representing
E. together to represent

Here, this dash is used correctly. The answer is (A).