whatdo you mean by capacitor
 

Solution
It is a electrical device used to store charge. It is also called condenser.
Capacitance is capacity to store charge on a conductor. It's unit is Farad (F) or Coulomb/volt. It's denoted by 'C'. 
mathematically capacitor is charge stored per unit volt is called capacitance. Formula for capacitance is $C=\frac{Q }{V } where Q is charge and V is voltge/potential of capacitor$