'Understood' in the Bible

And I, Daniel, fainted, and was sick certain days; then I rose up, and did the king's business: and I wondered at the vision, but none understood it.

in the first year of his reign I, Daniel, understood by the books the number of the years whereof the word of Jehovah came to Jeremiah the prophet, for the accomplishing of the desolations of Jerusalem, even seventy years.

In the third year of Cyrus king of Persia a thing was revealed unto Daniel, whose name was called Belteshazzar; and the thing was true, even a great warfare: and he understood the thing, and had understanding of the vision.

And I heard, but I understood not: then said I, O my lord, what shall be the issue of these things?