'Thousands' in the Bible

and with him ten princes, of each father's house a prince, out of all the tribes of Israel; and each of them was head of a father's house, of the thousands of Israel.

And the children of Reuben and the children of Gad and the half tribe of Manasseh answered and said to the heads of the thousands of Israel,

And when Phinehas the priest and the princes of the assembly and the heads of the thousands of Israel that were with him heard the words that the children of Reuben and the children of Gad and the children of Manasseh spoke, it was good in their sight.