a belt of shell beads used by eastern Indians, especially the Iroquois, as a mnemonic device for recording the terms of treaties etc. or as a mark of honor.
1760  Both of them . . . are made into small oblong or cylindrical beads, which are bored and stringed together, and these are called necklaces, or belts of Wampum.
1893  The commissioners were given a belt of wampum, and the council adjourned to Sandusky. . . .
1905  It was quite common for an Indian chief to bestow a belt of wampum upon a white man for favours received.