‘Onboard' or ' On Board': What's the Difference Between the Two?

By Shanea Patterson, updated on January 10, 2023

Is someone ‘onboard’ a ship or ‘on board’? And what’s the difference between the two? We’ll cover that in this article, plus teach you how to use the correct version in a sentence.

Not a fan of long answers? Here’s the short one.

  • ‘Onboard’ is an adjective that means attached. It’s also a verb that means to acclimate new hires to a company.
  • ‘On Board’ is an adverb or prepositional phrase, and it means safely aboard a vessel or in agreement.

‘On Board’ or ‘Onboard’ – What’s the Difference?

 As you just learned, the difference between ‘onboard’ and ‘on board’ is pretty significant.

‘Onboard’ is an adjective that means attached. It’s also a verb that means to acclimate new hires to a company.

‘On Board’ is an adverb or prepositional phrase, and it means safely aboard a vessel or in agreement.

Therefore, you need to be careful about how you use both terms since they don’t mean the same thing. They’re essentially homophones.

How to Use ‘Onboard’ vs. ‘On Board’ Correctly

Only use ‘onboard’ when you’re trying to say ‘attached’ or ‘to acclimate new hires to a company.’

Use ‘on board’ when you’re referring to being safely onboard a vessel or in agreement. 

Definition and Meaning of ‘Onboard’

The Merriam-Webster definition of ‘onboard’ is: “carried within or occurring aboard a vehicle (such as a satellite or an automobile).”

Definition and Meaning of ‘On Board’ 

The Merriam-Webster definition of ‘on board’ is: “a piece of sawed lumber of little thickness and a length greatly exceeding its width,” “a surface, frame, or device for posting notices,” “blackboard,” “a flat usually rectangular piece of material (such as wood) designed for a special purpose: such as 1) surfboard, 2) skateboard, 3) springboard 4) boards,” “basketball: backboard,” “switchboard,” “a group of persons having managerial, supervisory, investigatory, or advisory powers,” and “an exposed dummy hand in bridge.”

Other definitions are: “to go aboard (something, such as a ship, train, airplane, or bus),” “to put aboard,” and “to cover or seal off with a long, thin, and often narrow piece of sawed lumber: to cover or seal off with boards > usually used with up."

Synonyms of the word include:


  • Association
  • Club
  • Consortium
  • Fraternity
  • Brotherhood
  • College
  • Council
  • Guild
  • Chamber
  • Congress
  • Fellowship
  • Gild
  • League
  • Society
  • Organization
  • Order
  • Sodality


  • Cater
  • Feed
  • Victual
  • Provision

How to Use ‘Onboard’ and ‘On Board’ in a Sentence

Now that you know how to tell the difference between ‘onboard’ and ‘on board,’ let’s talk about how to use them in a sentence correctly.


  • I have to onboard a few employees this afternoon, and I’m not looking forward to it.
  • Did you fulfill the onboarding request from the partners? You better get on it.
  • I don’t remember the process of onboarding new employees taking this long before.
  • The onboard process is pretty straightforward, with explicit
  • This car has an onboard computer built right into it. We can listen to music or watch movies.
  • I don’t think this old model would have an onboard satellite.

‘On Board’

  • Is every passenger on board and checked in? We have to get this cruise ship moving.
  • Miss Hamilton wasn’t on board when the incident took place. She can be eliminated as a suspect.
  • A passenger on board ran butt naked across the deck last night.
  • I can’t believe I’m on board such a luxurious cruise ship. I never want to go home.
  • Have you seen what they’re serving for breakfast every morning on board the ship?
  • I’m afraid of being on board a ship. The last time I was on the water was a disaster.

Final Thoughts on ‘Onboard’ and ‘On Board’

Now that you know what ‘onboard’ and ‘on board’ mean, you know that they can’t be used interchangeably. You also know how to use them in a sentence correctly, thanks to the above examples. Use them as a guide when crafting your own sentences.

If you ever get stuck, you can always come back here and double-check. We’ve got a whole library of content dedicated to explaining confusing words and phrases in the English language.

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Written By:
Shanea Patterson
Shanea Patterson is a writer based in New York and loves writing for brands big and small. She has a master's degree in professional writing from New York University and a bachelor's degree in English from Mercy College.

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