a sealed, floating box that carries chosen lives safely through deadly water
This word names a vessel, but a very particular kind: a watertight box, sealed with pitch, that has no sail, no oar, and no rudder. It is not a ship that anyone steers. It is a container that simply floats, keeping those inside alive while the water outside would kill them. Everything about it points away from human skill and toward being kept safe by God alone.
The word is striking because the Hebrew Bible uses it for only two objects: the great vessel that carries Noah, his family, and the animals through the flood, and the little reed basket in which baby Moses is hidden on the Nile. Nothing else in the Bible is ever called by this word. That narrow range is deliberate. The writer of Exodus reaches back and picks the same rare word the flood story used, so that the basket cradling Moses quietly echoes the vessel that saved Noah. In both stories one chosen life is sealed inside a box and brought safely through water that means death for everyone outside.
The two uses differ only in scale and setting, not in meaning. One is an enormous three-decked structure of gopher wood; the other is a baby's basket of woven papyrus. But both are the same idea: a passive, sealed craft of rescue. The single English problem is that the older Bibles call the large one an "ark," which makes readers confuse it with the gold-covered ark of the covenant. In Hebrew those are two completely different words for two completely different things.