a word, or the matter that word is about: anything said, and equally the affair, event, or thing being spoken of
This one Hebrew noun reaches across two ideas English keeps in separate words: the word that is spoken, and the thing the word is about. It can mean an utterance, a speech, a command, or a promise, and just as naturally a matter, an affair, an event, or even a legal case. English has the same stretch in the word matter, which can be a topic of speech, the business at hand, or a serious affair, and it is the closest single word for what this Hebrew noun does.
The two are not separate meanings layered into every verse. They are the connected ends of one idea: speech, then the content of the speech, then the topic spoken of, then the state of affairs itself. Which end is in view is fixed by the context, not carried in the word. Most often it is simply something said. From there it leans in particular directions: when God is the speaker it becomes the message or command he sends, the ordinary noun behind the phrase the word of the LORD; in a courtroom it is the case being argued; in a narrator's hands it is the affair that took place.
A caution this entry takes seriously: an older view held that for ancient Israel the very word carried a built-in power, a charged thing that made happen what it said. Careful study has shown that this is not what the noun itself means. The Old Testament does teach that God's word accomplishes what he sends it to do, but that force belongs to God who speaks and keeps his word, not to some potency stored inside the noun. So the range here is the ordinary, wide range of a common noun for speech and the things speech is about, and nothing more is hidden in the word.