"Word" is the shortened form of the phrase: "my word is my bond" which was originated by inmates in U.S. prisons. The longer phrase was shortened to "word is bond" before becoming "word," which is most commonly used. It basically means "truth." Or "to speak the truth."

When you’re so bored like me that you type that word just to see a definition

New York slang for guaranteeing something you will do (most of the time, it’s an exaggeration)

A versatile declaration, originating (more or less) in hip-hop culture.

"Word" has no single meaning, but is used to convey a casual sense of affirmation, acknowledgement, agreement, or to indicate that something has impressed you favorably.

Its usage among young blacks has been parodied ad nauseam among clueless suburban whites.

An arbitrary sequence of sounds used to convey meaning, invented by people a long time ago; can be written as a sequence of letters or as a character.

To be serious or honest about something.

Typically means you are at a loss for words. Or you have nothing to say on a matter.