Main Entry: ¹bal·last

Pronunciation: \ˈba-ləst\

Function: noun

Etymology: probably from Low German, of Scandinavian origin; akin to Dan & Swedish barlast ballast; perhaps akin to Old English bær bare & to Old English hlæst load, hladan to load — more at lade

Date: 1530

1 : a heavy substance placed in such a way as to improve stability and control (as of the draft of a ship or the buoyancy of a balloon or submarine)
2 : something that gives stability (as in character or conduct)
3 : gravel or broken stone laid in a railroad bed or used in making concrete
4 : a device used to provide the starting voltage or to stabilize the current in a circuit (as of a fluorescent lamp)

— in ballast of a ship : having only ballast for a load