Hyphen | Dashes | Em
Dash | En Dash
Hyphens and Dashes
Hyphens are used for different reasons than dashes. The following
paragraphs explain the distinctions.
Use a hyphen
- When two- or three-word modifiers precede the noun.
cost-competitive semiconductor production
- To reduce confusion or ease the reading of compound words and
some prefixes for words.
re-sign (as opposed to resign), burn-in, P-N junction, non-deposition
NOTE: Most prefixes are no longer hyphenated. A usage table for
common prefixes is in The Chicago Manual of Style.
- To add a prefix to a proper noun.
- To show relationship when the first element or prefix for a
compound term must temporarily stand alone.
one- or two-page description, high- or low-level radiation
Do not use a hyphen
- When a an adjective clearly modifies the noun following it.
high volume manufacturing
- When compound modifiers follow the noun.
high-volume semiconductor production that is cost competitive
- When compound modifiers combine an adverb and adjective.
highly sensitive material
optimally focused lens
- When adjectives are composed of foreign words (unless they
are always hyphenated).
in situ measurement
a priori argument
There are two basic types of dash: an em dash (-) and an en dash
(-). When using dashes, keep in mind
Dashes are not surrounded by spaces.
The first word after a dash within a sentence is not capitalized
unless it is a proper noun.
Use an em dash to
Set off an explanatory or appositive series
The company has established a worldwide customer base in all major
markets-the U.S., Europe, Japan, Korea, and Taiwan.
Set off parenthetical elements more sharply and emphatically
The 1990 plan-both the planning process and the finished product-attests
to the increasing level of maturity and effectiveness at SEMATECH.
Set off a phrase that typically requires commas, but one in which
using commas would cause confusion
Knowledge from the SEMATECH member companies, America's equipment
and material suppliers (SEMI/SEMATECH), and the Department of Defense
(DOD) are brought into SEMATECH-along with information from American
universities, research institutions, government laboratories and
agencies, and the Semiconductor Research Corporation (SRC).
Use an en dash to indicate a range.