behold, look: a pointing word that grabs the listener's attention and directs it at what comes next.
This is not really a word you translate so much as a gesture you make with language. Its one job is to point. It tells the listener to stop and pay attention, then aims that attention at whatever follows: a person standing right there, a thing just noticed, a piece of news, or something about to happen. Older English Bibles render it "behold" or "lo," and newer ones often use "look," "see," "now," or simply leave it out. None of those is wrong, because the word has no fixed meaning of its own; it takes its color from the scene.
What unites its many uses is this act of pointing, and much of the time the pointing carries a jolt of the unexpected. The speaker is not just noting a fact but flagging that it should catch the listener off guard, or that it matters more than the flat words would suggest. In a story, it often works like a camera cutting from the narrator's wide view to a character's own eyes, so that we suddenly see what that person sees, at the moment they see it. In prophecy, it presses a coming event right up against the present, as though it were already underway.
Because it does this attention-work rather than naming a thing, its force lives in tone and timing more than in dictionary meaning. That is why it is one of the most-used and least-noticed words in the Hebrew Bible: it shapes how a scene lands on the reader without ever adding a fact to it.