1. (n.)ballast a heavy material carried on a vessel to control draft and stability or a balloon to control altitude.
2. ballast gravel or broken stone placed under the ties of a railroad.
3. ballast a device that maintains the current in an electric circuit at a constant value and may also provide the starting voltage, as in a fluorescent lamp.
4. (v.t.)ballast to furnish with ballast.
Etymology: (1520–30; < MLG, perh. ult. < Scand; cf. early Dan and Sw barlast=barbare1+last load)
Definition of 'Ballast'
Princeton's WordNet
1. (noun)ballast any heavy material used to stabilize a ship or airship
2. (noun)ballast coarse gravel laid to form a bed for streets and railroads
3. (noun)ballast an attribute that tends to givestability in character and morals; something that steadies the mind or feelings
4. (noun)ballast resistor, ballast, barretter a resistor inserted into a circuit to compensate for changes (as those arising from temperature fluctuations)
Definitions of Ballast 
