to understand by telling things apart: to grasp what something really is, why it matters, and how it differs from what is near it
At its core this word is not about storing facts but about discerning, seeing the difference between one thing and another and so grasping what is actually going on. The picture behind it is sorting and separating: the person who understands is the one who can tell the wise from the foolish, the true from the false, the cause from its effect. That is why the same word covers a quiet inner grasp, a settled quality of good judgment, the work of opening someone else's eyes, and the slow act of looking hard at something until it makes sense.
These senses are one act seen from different angles. To understand (sense 1a) is the bare event of grasping. To be discerning (1b) is that grasp settled into a person as a trait, the mark of someone you would trust with a hard decision. To give understanding (1c) is causing that grasp in someone else, the work of a teacher or of God opening a mind. To consider carefully (1d) is the deliberate looking that produces the grasp, attention paid until the meaning surfaces.
The word lives most at home in Israel's wisdom writings and in Daniel, where understanding is both a gift and a discipline. It is often paired with knowing and with wisdom, yet it keeps its own edge: not raw information, and not cleverness, but the seeing-through that lets a person judge rightly and act well.