onboard

The word “onboard” means on or inside a ship, aircraft, train, or other vehicle. In plain terms, being on a vehicle, or (in business) getting someone set up as a new employee or user.

“Onboard” is pronounced on-BAWD (/ɒnˈbɔːd/ in IPA).

Here is “onboard” used in a sentence: “Passengers were asked to remain onboard during the delay.”

The opposite of “onboard” — its antonyms — is offboard.

Depending on how it is used, “onboard” can be an adverb and a verb.

“Onboard” is an uncommon word in modern English.

“Onboard” has 2 distinct senses listed in this dictionary. The most common is: on or inside a ship, aircraft, train, or other vehicle.

Both mean on or inside a ship, aircraft, or train, and they are largely interchangeable as adverbs. "Onboard" is more common in modern travel and computing contexts, while "aboard" feels slightly more traditional or nautical.

As an adverb meaning inside a vehicle, and as a verb meaning to integrate a new employee, "onboard" is written as one word. Some style guides still use "on board" as two words in the adverbial sense, so both forms appear in edited text.

In business and HR, "onboard" is a verb meaning to integrate a new employee or customer into an organization or system, covering training, paperwork, and orientation. This usage has become standard in corporate English since the term "onboarding" spread through HR departments.