# Hyphenation and Compounds

Entries about hyphenation, prefixes, suffixes, compound modifiers, and adjective/predicate adjective distinctions from the Apple Style Guide.

## Entries

### anti (prefix)
Close up except before *i* or a capital letter.

> antiphishing, antivirus
> anti-intellectual, anti-Linux
> Exception: anti-replay

### auto (prefix)
Close up except before o.

> autoanswer, autoconfiguration, autosync
> auto-oxidation

See also [prefixes](#prefixes).

### based
Use a hyphen in compound adjectives that include *based* when they precede a noun.

> application-based services, Windows-based computer

Use an en dash (Option-Hyphen) if *based* follows a term with two or more words.

> Windows XP–based computer

Don't use a hyphen or an en dash in predicate adjectives that include *based*.

> Each track in a sequence is assigned an index value that is zero based.

### built-in (adj.), built in (pred. adj.), built into (pred. adj.)
In headings that use title-style capitalization, don't capitalize *in* (exception to the rule of capitalizing the second word of a hyphenated compound).

> Built-in Apps on Your MacBook [heading]
> You can use the built-in microphone or an external microphone.
> Mac Pro has 512 GB of flash storage built in.
> Two-factor authentication is built into iOS 9 and later.

### co (prefix)
Close up except before a few words beginning with o.

> coexist, cooperate, coprocessor, coworker
> co-op, co-owner

### double
Hyphenate compound adjectives beginning with *double*.

> double-precision, double-sided, double-wide

### dual
Hyphenate compound adjectives beginning with *dual*.

> dual-band, dual-channel, dual-link

### e
Short for *electronic*. Hyphenate terms using the short form: *e-commerce*, *e-learning*. Exceptions include *email* and *ebook*. In titles that use title-style capitalization, capitalize as follows: *The Growth of E-Commerce*.

### full
Use a hyphen in compound adjectives beginning with *full*.

> full-duplex, full-featured, full-height, full-page, full-screen, full-size

Don't use a hyphen with *fully*.

> fully buffered, fully charged, fully loaded

### half
Use a hyphen in compound adjectives beginning with *half*.

> half-duplex, half-height, half-hour, half-length

### high
Use a hyphen in compound adjectives beginning with *high*.

> high-bandwidth, high-definition, high-level, high-quality, high-resolution

### hyphenation
In general, hyphenate two words that precede and modify a noun as a unit. Follow this rule especially when:

- Confusion might result if the hyphen were omitted, as in *parameter-list pointer* or *read-only memory*.
- The second word is a past or present participle, as in *binary-coded decimal* or *color-matching algorithm*.
- The two modifiers are a number or a single letter and a noun or a participle, as in *32-bit color* or *D-shaped connector*.

Follow these guidelines for specific cases:

- *Units of measure:* When you use a spelled-out unit of measure in a compound adjective, hyphenate the compound (*27-inch screen*). When you use an abbreviation or a metric unit of measure, including *KB, MB, mm,* and so on, don't hyphenate (*500 GB hard disk*).
- *Location compounds:* Hyphenate compounds such as *lower-left corner*, *top-right portion*.
- *Adverbs:* Don't hyphenate compounds with *very* or with adverbs that end in *-ly*.

> very high speed
> recently completed project

- *Keyboard shortcuts using combination keystrokes:* Use hyphens to signify that the first key or keys should be held down while the last key is pressed. (Don't use hyphens if each key should be pressed and released separately.) Make sure you explain this convention on first use.

> Control-Shift-N
> Esc N

See also [dash (en)](punctuation.md#dash-en).

### like (suffix)
Close up words ending with *like* unless the word is a proper name or a compound term, or the resulting word is difficult to read.

> businesslike, Ethernet-like, typewriter-like

### mega (prefix)
Close up words beginning with *mega*.

> megabit, megabyte, megahertz, megapixel, megawatt, megawide

### mini (prefix)
Close up except before a vowel, a proper noun, or an abbreviation.

> minicircular connector, minitower
> mini-application, mini-DVI, mini-VGA

### multi (prefix)
Close up except before *i*.

> multiplayer, multiprocessor, multitasking, multithreading, multiuser
> multi-item

### non (prefix)
Close up except before a proper noun, a proper adjective, an abbreviation, or an acronym, or when the resulting word would be difficult to read.

> noncompliant, nondestructive, nonstandard
> non-Apple, non-Mac, non-USB

See also [prefixes](#prefixes).

### post (prefix)
Close up except before a proper noun or a date.

> postgraduate, postmortem, posttest
> post-WWDC event, post-2017
> Exception: post-production

### pre (prefix)
Close up except before a proper noun or a date.

> preinstalled, preexisting, preproduction
> pre-WWDC event, pre-2025
> Exception: pre-order

### prefixes
In most cases, close up prefixes (such as *multi*, *non*, *post*, and *pre*) with the following word. Exceptions:

- Compounds that contain proper nouns (*non-Apple*)
- Compounds with double *i*'s or double *a*'s (*anti-inflammatory*, *meta-analysis*)
- Compounds that are homographs or could be misread (*re-cover*)
- Compounds with double prefixes (*sub-subentry*)
- Compounds that contain a compound term (*non-self-sustaining*)

See *The Chicago Manual of Style* for more examples.

### quad
Hyphenate compound adjectives beginning with *quad*.

> quad-band, quad-channel, quad-core, quad-port

### quality
Don't use *quality* alone as an adjective; include a modifier. The compound adjective is hyphenated.

> broadcast-quality, high-quality, professional-quality

### re (prefix)
Close up unless the resulting word creates another word.

> reenter, reinstall, reevaluate
> re-create (recreate), re-sort (resort)

### self
Use a hyphen in terms beginning with *self*.

> self-paced, self-playing, self-running, self-service

### single
Hyphenate compound adjectives beginning with *single*.

> single-button, single-core, single-layer, single-precision, single-processor

### size (adj.)
Hyphenate compound words ending with *size*. Not *sized*.

> letter-size, medium-size, pocket-size

### sub (prefix)
Close up words beginning with *sub*.

> subaccount, subdirectory, submenu, subnetwork

### super (prefix)
Close up words beginning with *super*.

> supercomputer, superfine, supermodern

### ultra (prefix)
Close up except before a vowel.

> ultrafast, ultralight, ultrasharp, ultrathin, ultrawide
> ultra-efficient

### wide
Use a hyphen in compound adjectives beginning with *wide*.

> wide-angle viewing, wide-format screen
> Exception: widescreen

Close up words that end with *wide*.

> companywide, enterprisewide, industrywide, systemwide, worldwide

If part of the compound is a proper noun, use a hyphen: *Apple-wide*.

### work
Close up the following words beginning with *work*.

> workflow, workforce, workgroup, workplace, workshop, workspace, workstation
