getting out of a disaster alive: both the escape itself and the people who come through it
This word sits at the meeting point of two ideas that English usually keeps apart: the escape from a catastrophe, and the survivors that escape produces. In some verses it names the act or the bare possibility of getting away safely (a way out, a deliverance). In others it names the concrete result: the band of people, or the scrap of a nation, left standing after the disaster has passed. Hebrew treats these as one word because they are one event seen from two ends, the rescue and the rescued.
The two senses shade into each other, and a handful of verses can be read either way. When Joseph says God sent him ahead to preserve a great one of these for his family, he can mean either a great deliverance or a great company of survivors, and translators split on it. That flexibility is built into the word rather than a flaw in it.
Over the course of the Old Testament this ordinary word for battlefield fugitives takes on enormous weight. Survivors of a fallen city (2 Kings 19:31), the fragment of a people that returns from exile (Ezra 9:8), and finally the rescued community on Mount Zion in the last days (Joel 2:32; Obadiah 1:17) are all named with it. Prophets pair it with a second word for what is left over, so that the two together mean a remnant that has come through by escaping, not merely a leftover. That is why the word carries so much hope: it names not just who is gone but who is saved.