O
- offline
Use to describe a device or account that’s not connected to the internet or a network. Be sure the context makes it clear what offline means.
If your email account is offline (not connected to the internet), you can’t send or receive mail.
In informal contexts, it’s OK to describe people as being offline, but use a more specific term if necessary for clarity.
Acceptable: If you want to go offline for a while, turn on Do Not Disturb.
Acceptable: You can read your saved articles at any time—even when you’re offline.
Preferable: You can read your saved articles at any time—even when you’re not connected to the internet.
See also online.
- offscreen (adj., adv.)
One word.
- offsite
One word.
- OK
Not okay.
- onboard (adj., v.), on board (pred. adj.)
In computing, onboard (short for on the board) refers to components attached to a circuit board or logic board. Use built in (as in built-in graphics card) or internal unless you need to make clear that a component is attached to a board.
In internal communications, it’s OK to use onboard as a verb: Onboard your new employee. Use two words when on board is an adjective following a verb: Make sure your employee is on board. Don’t use onboard as a verb in user materials.
- once
Don’t use when you mean after.
Correct: After you turn on the computer…
Incorrect: Once you turn on the computer…
- one-click (adj.)
OK to use to refer to actions or functions that are very simple.
From one-click fixes to detailed editing, there are a number of tools available in Photos.
Don’t use 1-Click.
- online
One word. Use to describe content or services that are available on the internet or a network.
Some books contain online content, which is stored on the web, not in the book file.
Safari keeps your information secure when you shop online.
In informal contexts, it’s OK to describe people as being online, but in most cases use a more specific term (for example, signed in or connected to the internet).
Acceptable: Follow these tips to keep your kids safe when they’re online.
Correct: To use Siri, you must have an internet connection.
Incorrect: To use Siri, you must be online.
You can refer to devices as online if the context makes it clear what that means.
Correct: You can locate your Mac if it’s online—awake and connected to a Wi-Fi network.
Incorrect: You can locate your Mac if it’s online.
See also offline.
- on/off switch
Not on/off button.
- onscreen (adj., adv.)
One word.
- onsite
One word.
- on-the-go playlist
Note hyphens.
- onto, on to
Use on to when on is part of the verb.
Correct: Hang on to the handles.
Correct: Lift the printer onto the table.
Incorrect: Lift the printer on to the table.
See also into, in to.
- open
Users open icons, folders, documents, and apps. See also close.
- opening display
Not splash screen. Opening display, startup display, and startup screen are all OK.
- open source (n., adj.)
No hyphen.
- operating system (n.), operating-system (adj.)
Note hyphenation of adjective. See also iOS; iPadOS; Mac operating systems; tvOS; visionOS; watchOS.
- optical disc
CDs and DVDs are optical discs. OK to use optical disc, optical media, or the type of CD or DVD. See also CD; DVD.
- optical drive
Use instead of CD drive or DVD drive to refer generally to drives that read from and write to (burn) optical discs (CDs and DVDs). Exception: Refer specifically to SuperDrive when appropriate. See also SuperDrive.
- optical inserts
- Optic ID
An authentication technology using iris recognition. Don’t precede with the. It’s OK to use Optic ID alone or in terms such as Optic ID technology.
You can use Optic ID to authorize purchases and unlock Apple Vision Pro.
- optionally
Avoid in user materials. Instead, describe the reason the user would perform the action. If it’s important to emphasize that the action is optional, you can say If you want to…
Correct: If you want to set a disk quota, enter the number and specify megabytes (MB) or gigabytes (GB).
Incorrect: Optionally, enter a disk quota and specify megabytes (MB) or gigabytes (GB).
Correct: To set a trust level, enter the command in Terminal.
Incorrect: Optionally, set the trust level by entering the command in Terminal.
- Option-click (v.)
Equivalent to press the Option key while you click.
To add a Bezier point, Option-click the path.
See also key, keys.
- Option-drag (v.)
Equivalent to press and hold the Option key while you drag.
To copy a bookmark, Option-drag it.
See also key, keys.
- Option key
To refer to the action of pressing the Option key while performing a mouse or trackpad action, use Option-click or Option-drag. See also Alt key.
- option names
For options and other onscreen elements of two or more words whose names are capitalized using sentence style, use quotation marks in text to avoid misreading.
Select the checkbox labeled “Keep lines together.”
- OS X
- OS X Server
See macOS Server.
- outbox
One word.
- outline font
Not outlined font.
- output (n., adj.)
Avoid as a verb; use write to, display on, print on, or print to.
- outside
Not outside of.
- over
Don’t use when you mean more than.
Correct: You can add more than 1000 songs.
Incorrect: You can add over 1000 songs.